JPH05288635A - Stress evaluator for constructing meeting asme standard - Google Patents

Abstract

PURPOSE:To achieve a stress evaluation efficiently on all stress lines of an analysis model by including an automatically stress line generating means and a stress evaluation means. CONSTITUTION:Identification number and analysis condition 001 of material to be used are read in. Then, data of analysis conditions and allowable stress values or the like 002 for each material identification number, a correspondence list 004 between element number and the material identification number, node number and coordinate values 005 thereof, the element number and connectivity 006 thereof and results 007 of structural analysis are read in. A stress line is generated 6-2 automatically and a development of the results of axially symmetrical analysis is performed to the results of three-dimensional analysis as required. Finally, a stress evaluation 6-4-1 is accomplished. A file 009 of the results of the stress evaluation is generated through an output device 7. A contour line chart of the results of the stress evaluation of various scales are displayed on an analysis model. Moreover, a physical property value data used for the analysis is subjected to a processing of plotting 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The disclosed technology belongs to the technical field of stress evaluation according to the ASME standard for structural analysis of nuclear containers, pressure containers for chemical plants and the like.

[0002]

2. Description of the Related Art In stress evaluation according to the ASME standard (references 1, 2, 3, etc.), a load on a structure is a load control type load (eg, internal pressure, mechanical load, etc.) and a displacement control type load. The stress generated by the former is defined as the primary stress, and the stress generated by the latter is defined as the secondary stress. Furthermore, each stress component is linearized in the thickness direction for each load,
It is classified into membrane stress, bending stress, and peak stress, and these are used to define the primary stress limit, the primary + secondary stress limit, the stress limit for fatigue, and the like. Therefore, a portion where the above limitation becomes a problem is determined from the analysis result, and a stress line (reference document 1 in Reference 4 or Reference 8 in the thickness direction) is determined at this location in the thickness direction.
3) must be set, stress must be evaluated on each line, and structural integrity must be confirmed. In addition, today, Document 5
As described above, a post-processing system based on finite element analysis is adopted to improve the calculation accuracy and save labor. On the other hand, in the field of structural analysis in recent years, large-scale and high-level analysis has become possible due to remarkable advances in hardware and software. In particular, general-purpose structural analysis program ABAQUS (reference 6), etc., and pre- and post-processor PATRAN (manufactured by PDA Engineering, USA) (reference 7)
, Etc., for example, the shape of an axisymmetric structure composed of an axisymmetric element (Fig. 1), a three-dimensional solid element (Fig. 2), or a three-dimensional structure composed of a four-sided shell element (Fig. 3). Data creation (preprocessing), structural analysis, drawing processing (postprocessing)
It is possible to process a series of analysis tasks such as Furthermore, it is also possible to create an analytical model with the stress line assumed from conventional experience in mind.

[0003]

However, according to the conventional stress evaluation method, (1) a person determines a stress line from the iso-stress diagram after analysis, and inputs this into a separate KOMOSS (reference 5) or the like. However, the two-dimensional analysis was relatively easy, but the three-dimensional analysis was considerably difficult. (2) Generally, the place where excessive stress is generated is different from the expected place due to stress limitation such as primary stress, primary + secondary stress, and fatigue evaluation. For this reason, it was necessary to set a considerable number of stress lines in order to confirm the soundness of the strength of the entire structure, and it took a lot of labor and time to prepare a calculation manual by manpower. There was a problem such as. An object of the present invention is to provide an evaluation device capable of automatically generating stress lines in the entire analytical model and performing stress evaluation for all the stress lines in order to solve the above problems.

[0004]

In order to achieve the above object, the present invention performs a structural analysis of a measurement object, and based on the analysis result, the stress line in the thickness direction of the measurement object conforms to the ASME standard. In a device for performing stress evaluation, a physical property value memory that stores various physical property values for each material in advance, condition input means for inputting the material used for the measurement object and analysis conditions, and the condition input Used material-physical property value correspondence memory for temporarily storing the physical property value corresponding to the material input by the means from the physical property value memory, and analysis conditions and allowable stress corresponding to the material input by the condition input means Material used for searching and temporarily storing data such as data, analysis condition correspondence memory, data on the shape of the object to be measured and correspondence between structural element and its material, nodes and Structural analysis preprocessing means for creating shape data consisting of coordinate values, structural elements and their connectivity, etc., shape data obtained by the structural analysis preprocessing means, and physical properties stored in the material-physical property value correspondence memory. From the structure analysis means for performing the structure analysis of the measurement object from the value, the analysis result obtained by the structure analysis means, and the shape data obtained by the structure analysis preprocessing means,
A stress line automatic creation means for automatically creating stress lines of all elements constituting the analysis model of the measurement object; and a stress evaluation means for performing stress evaluation on all stress lines obtained by the stress line automatic creation means,
It is configured as a stress evaluation device for a structure according to the ASME standard, characterized in that it is provided with an output means for outputting an evaluation result by the stress evaluation means.

[0005]

In the present invention, all the stress lines are created by the stress line automatic creating means from the data such as the physical property values for each material stored in advance, and the stress evaluation values on all the stress lines are achieved by the stress evaluating means.

[0006]

EXAMPLES Next, examples in which the present invention is embodied will be described, and finally the application examples thereof will be described. Fig. 4 shows a search device (1) located before and after the "stress evaluation device according to ASME standard" (6), structural analysis preprocessing (2), structural analysis (3), and after structural analysis. It is a functional block diagram of a device of this example provided with functions of processing (4) and post-processing (8) of stress evaluation results. The following (reference numerals) correspond to the block numbers in FIG.

(A) Material Physical Property Retrieval Device (1) FIG. 5 shows a detailed functional block diagram of the device. In this apparatus, first, input data (001, identification number of used material, and analysis condition) is read (condition input means). Here, the analysis conditions are design temperature, design pressure, operating temperature,
It includes the operating pressure and the number of repeated operations, and includes all data necessary for stress evaluation of structures. Also, in this input data, analysis conditions are defined for each identification number of the material used, and are already stored in the computer file (physical property value memory) by the search circuit (1-1) of each material. From material data (1-002 to 1-009) and correspondence table file (1-001), analysis conditions for each material identification number, allowable stress value, design fatigue curve, number of repeated operations, etc., all necessary for stress evaluation Data is output to a file (memory corresponding to analysis conditions) (002). Further, temperature dependence of various physical property values of each material, and data for outputting a drawing such as a fatigue design curve are output to a file (memory corresponding to physical property values) (003) in a predetermined format. (B) Preprocessing of structural analysis (2) Preprocessing is usually performed by PATRAN or the like, and shape data of an analytical model is created (structural analysis preprocessing means). This shape data is obtained from the correspondence table (004) between element numbers and material identification numbers, the coordinate values of nodes (005), and the connectivity of elements (006, the relationship between the element numbers and the node aggregates that form the elements). It is composed and is output to each predetermined file.

(C) Structural Analysis (3) (Structural Analysis Means) A general-purpose structural analysis program ABAQUS or the like is used for structural analysis. The input data of this program is the shape data (005, 006) of the analysis model, the physical property value data for each material identification number (003, for example, Young's modulus, thermal conductivity, specific heat, etc., and usually has temperature dependence. ), Internal pressure, mechanical load, and thermal load (steady or unsteady), and the analysis result is output to the file (007) in a predetermined format. For post-processing of structural analysis, PATRAN is usually used.
Etc. are used to draw a deformation diagram and a contour map (008) of stress values. (D) Stress evaluation device according to ASME standard (6) In the device of this example, the following processes a to d are performed. First, the data of 002, 004, 005, 006 and 007 is read, and then the stress line is automatically generated (6-
2) Then, if necessary, the axisymmetric analysis result is expanded to a three-dimensional analysis result (6-3), and finally stress evaluation is performed (6-4), and the output device (7) is used. A stress evaluation result file (009) is generated.

A. Data reading circuit (6-1, 6-
1-1) Shape data (005,006) of analysis model and 0
The data of 02,004 is read (6-1). The analysis result (007) is read from the circuit 6-1-1. b. Stress line automatic generation circuit (6-2) (stress line automatic generation means) This circuit connects the stress line to the element connectivity (the relationship between the element number and the node number, and the node number (or integration point number) and surface number determined from it). (Relationship with
Alternatively, it is characterized in that it is automatically determined from the relationship between the connectivity of elements and the node coordinate values (or integration point coordinate values). Below is a specific example of a method that uses the connectivity of elements. b. Method of using one-element connectivity (when using node numbers) The procedure of this method is shown in FIGS. 6, 7, and 8. Also in FIG.
Figure 1 shows an outline of the automatic circuit for creating stress lines. For example, in the case of an analytical model composed of 3D solid elements,
As shown in FIG. 6, three layers of elements i, j, and k are assumed in the thickness direction. If the inner surface is considered to be the third surface shown in FIG. 2 when creating the analytical model, the outer surface becomes the fifth surface shown in FIG. Furthermore, since the node numbers forming each element are regularly set in the space from 1 to 8 in FIG. 7,
As shown in FIG. 8, four vectors can be set in the thickness direction for each element. As a result, four stress lines (that is, vectors AE, BF, C) in the thickness direction of the elements i, j, k.
G, DH) can be automatically determined. Next, if this method is applied to all the elements constituting the analysis model as shown in FIG. 9, stress lines will be automatically generated without exception in the thickness direction.

In order to have generality, this circuit has the following characteristics. B) If the number of elements in the thickness direction is other than 3, the number of element detections in the block diagram of FIG. 9 is automatically adjusted, and the fifth surface is a free surface (that is, not connected to any element).
After confirming that, the number of elements in the thickness direction is determined. As a result, four stress lines are automatically generated by the same method as above. B) In the case of an analytical model composed of two-dimensional axisymmetric elements, the method similar to that for three-dimensional solid elements is possible. Figure 1
If the first surface shown in Fig. 4 is the inner surface and the third surface is the outer surface, the stress lines will be created for all element rows in the thickness direction (that is, for the entire structure) by the same method as in Fig. 9 and b). It is automatically generated. In the case of the quadrilateral shell of FIG. 3, the structural analysis program itself outputs a plurality of stress values in the wall thickness direction for each node, so there is no need to automatically generate stress lines. C) The designation of the inner surface (or outer surface) and designation of the surface number in the above a) and b) can be changed appropriately according to the analysis model.

B. Method using 2-element connectivity (when using integration point position) As a method of generating a stress line, search for element coupling in the thickness direction is performed b. There is a method of using the same method as that of No. 1 and using the integration point position without using the node position for the stress line vector. Like the connectivity, the integration point position is generated with regularity, so it is uniquely determined with mathematical regularity inside the various elements used (however, it is used in the structural analysis program used and in the program). Depends on the elements that are). As a result, in the case of a three-dimensional solid element, for example, a single stress line or a plurality of stress lines are generated in the thickness direction in the element of FIG. The same applies to the case of a two-dimensional axisymmetric element. However, when this method is used, the stress evaluation result on the stress line is interpolated as a nodal value to a nearby nodal point when the nodal value is used for drawing in the post-processing drawing process such as PATRAN. Etc. must be calculated separately.

C. A circuit that expands the analysis result of an axisymmetric object subjected to an axisymmetric load to the three-dimensional structural analysis result (6-3) This circuit shows the analysis result of an axisymmetric structure subjected to an axisymmetric load, and the three-dimensional structural analysis result. It is a circuit that expands to. For example, a non-axisymmetric external force and an axisymmetric load such as an internal pressure load and a thermal load may act on an axisymmetric structure such as a nozzle portion of a pressure vessel. In such a case, this circuit performs the predetermined analysis by using the axisymmetric analysis model of FIG. 11 for the axisymmetric load and the three-dimensional analysis model of FIG. 12 for the non-axisymmetric load. It has a function of expanding the result into a three-dimensional analysis result. In particular, when the thermal load is unsteady, using this circuit can significantly reduce the calculation time. As for the internal pressure load, the analysis by the three-dimensional analysis model may be more efficient in some cases, and thus the analysis by both models is provided. A functional block diagram of this circuit is shown in FIG. First, when operating this circuit, the three-dimensional structure analysis (3-1) and the two-dimensional structure analysis (3-2) are performed, and the stress line automatic creation circuit (6-2) Target the analytical model. Next, the axisymmetric structure analysis result (007-2) is read from the analysis result reading device (5), and the circuit (6-4) is read.
Expand to 3D analysis results with. However, the element division of the arbitrary cross section of the 3D analysis model is the 2D analysis model (Fig. 11).
Must be the same as.

D. Stress evaluation circuit (6-4) (stress evaluation means) As shown in the functional block diagram of FIG. 4, this circuit includes a stress evaluation circuit (6-4-1) on each stress line and a stress value coordinate conversion circuit. (6-4-1-1), stress classification circuit (6-4-1-2), stress evaluation circuit (6-4-1-3)
It is composed of First, the analysis result is read from the analysis result reading circuit (5), and then stress evaluation is executed on all stress lines. The stress evaluation result is output from the output circuit (7) in a predetermined format in the stress evaluation. Result file (0
09). This circuit has the following functions. d. 1 Operate the stress evaluation circuit (6-4-1) for any stress line, and then 6-4-1, 6-4-1
Execute -2, 6-4-1-3 and store the stress evaluation result. d. 2 In the stress value coordinate conversion circuit (6-4-1-1), each value of the stress component on the stress line (usually defined in the global coordinate system) is converted into a stress line based coordinate system. Coordinate conversion to the value of. d. 3 In the stress classification circuit (6-4-1-2), the stress distribution on the stress line generated by an arbitrary load is calculated in Reference 4
The stress is classified into each component of average stress, bending stress, and peak stress by the method described in (4) or the method according to reference 13 in reference 8. d. 4 In the stress evaluation circuit (6-4-1-3), all the stress evaluations required by the standards are defined in various standards that define stress evaluations in accordance with Document 1, Document 2, Document 3, and ASME standards. Do the item. At that time, when the materials are different on the stress line like a dissimilar material joint, regarding the allowable stress values such as the allowable stress value and the design fatigue curve,
Use the allowable value of the material on the safe side.

(E) Post-processing of stress evaluation result (8) (output means) Stress evaluation result defined in various standards (Reference 1, Reference 2, Reference 3, etc.) (for example, allowable stress of primary stress value) A contour map of the ratio to the value, the ratio of the primary + secondary stress value to the allowable stress value, fatigue damage, etc.) is displayed on the analytical model. As a result, the stress evaluation result of the structure can be confirmed by the image. PATRAN or the like is used for this post-processing. (F) Drawing of physical property data (9) The physical property data used for the analysis is drawn. For example, it is a relationship diagram between allowable stress value and temperature, a relationship diagram between Young's modulus and temperature, a design fatigue curve, and the like. For this processing, PAT
RAN or the like is used.

(Application example) In the method for automatically creating a stress line, (D) bb. 13 to 17 show an embodiment in which the method 1 is applied. FIG. 13 is a three-dimensional analysis model of the pressure vessel, which is composed of three-dimensional solid elements.
14 and 15 show the result of automatically generating the stress line for the portion A in FIG. FIG. 14 is an enlarged view of part A in FIG. 13, in which the solid line is the stress line and the wavy line is the element dividing line. FIG. 15 is a diagram of stress lines of the entire analysis model. FIG. 16 shows a contour map of fatigue damage (based on ASME Section 8, div. 2) from the stress evaluation results. In the figure, the maximum fatigue damage occurs at the B part, and an enlarged view of it is shown in FIG. From this figure, the fatigue damage exceeds 0.90, but it is smaller than 1.0, and it can be confirmed that fatigue cracks do not occur. Although fatigue damage is shown here, the ratio of the primary stress value to the allowable stress value, the ratio of the primary + secondary stress value to the allowable stress value, etc. can also be displayed in the same contour map, and each stress limit Whether or not is satisfied can be easily confirmed visually. Also, in the case of an axisymmetric structure or a plate structure, it can be confirmed by the same processing.

(References) 1. ASME Boiler and Pressure Vessel Code,
Section 3, "Rules for Construction of Nuclear Power
Plant Components, "Div. 1, SubsectionNB, Class 1
Components, and Section 8, "Rules for Constr
auction ofPressure Vessels, "Div. 2-Alternative Ru
les, The American Society of Mechanical Enginee
rs, New York, NY, 1986 Edition. 2. The ASME Boiler and Pressure Vessel
Code, Code Cases, Nuclear Components N-47-21 Class
1 Components in Elevated Temperature Service, 198
3.3. 3. Technical standards for structures, etc. related to nuclear facilities for power generation (Notification 501) 4. Kroenke, WC, et al., "Component Evaluat
ion Using the FiniteElement Method, Pressure Vesse
l and Piping Technology-1985-A Decade of Progress,
The American Society of Mechanical Engineers. 5. Toshihiko Terakawa, finite element method post processor “KOMO
SS ", R & D Kobe Steel Technical Report, Vol. 30, No. 3 6. ABAQUS USER'S MANUAL, Version 4.8, 1990,
Hibbitt Karlsson & Sorensen, Inc. 7. PATRAN USER'S MANUAL, Relese 2.4, Se
ptmber 1989, PDAEngineering 8. JL Hechmer, GL Hollinger, "The AS
ME Code and 3DStress Evaluation ", Journal of
Pressure Vessel Technology, November 1991, Vol. 11
3, The American Society of Mechanical Engineers.

[0017]

The effects of the present invention are as follows. ASM is used for stress evaluation of axisymmetric structures and three-dimensional structures.
When performing stress evaluation according to E standard, (1) It is not necessary for a human to set a stress line, and labor saving and speeding up are possible. (2) By imaging the stress evaluation results, the evaluation accuracy is improved, the reliability of the calculation sheet is increased, and the calculation sheet is easy for a third party to understand. (3) In the conventional calculation form, the stress distribution map and stress evaluation table were created for each stress line.
It took a huge number of pages to complete the calculation, but this will be improved. And so on.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a node number order (1 to 8) of an axisymmetric element and a surface number (in the case of ABAQUS). Above is 4
Node element, the figure below shows 8 node element.

FIG. 2 Order of node numbers of three-dimensional solid elements (1 to 20)
The figure which shows the relationship between and the surface number (for ABAQUS).

FIG. 3 shows a quadrilateral shell element. Order of the node numbers of the three-dimensional quadrilateral shell element (1 to 4) (for ABAQUS). The upper figure shows 4-node elements, and the lower figure shows 8-node elements.

FIG. 4 is a functional block diagram of structural analysis and the stress evaluation device.

FIG. 5 is a functional block diagram of a material physical property value retrieval device.

FIG. 6 is a schematic diagram of a thickness-direction element array including element numbers i, j, and k. The case of an 8-node solid element of ABAQUS is shown.

7 is a diagram showing the order of node numbers (1 to 8) of each element in the element sequence of FIG.

FIG. 8 is a diagram showing a method of generating a stress line in the element array of FIG.

FIG. 9 is a functional block diagram in the case where the automatic stress line generation circuit (6-2) is composed of three layers of eight-node solid elements in the thickness direction.

FIG. 10 is a functional block diagram of a circuit that develops the analysis result of an axisymmetric structure subjected to an axisymmetric load into a three-dimensional structural analysis.

11 is a diagram showing an axisymmetric analysis model for explaining the circuit of FIG.

12 is a diagram showing a three-dimensional analysis model for explaining the circuit of FIG.

FIG. 13 is a diagram showing a three-dimensional analysis model (1/2 model, bird's-eye view from the inner surface) of the pressure vessel.

FIG. 14 is a diagram showing an automatically generated stress line in the section A of FIG. 13;

FIG. 15 is an overall view of an automatically generated stress line.

FIG. 16 is a contour map of fatigue damage by ASME Section 8 div. 2 (008).

FIG. 17 is a contour map (008) of fatigue damage in the B part of FIG.

Claims (1)

[Claims] 1. An apparatus for performing a structural analysis of a measurement object and performing stress evaluation according to the ASME standard for each stress line in the thickness direction of the measurement object from the analysis result, and various physical property values for each material. A physical property value memory for storing in advance, condition inputting means for inputting a material used for the measurement object and analysis conditions, and a physical property value corresponding to the material input by the condition inputting means. Used material-physical property value correspondence memory that is retrieved from the memory and temporarily stored, and used material-analysis condition correspondence that retrieves and temporarily stores the analysis conditions and allowable stresses corresponding to the material input by the condition input means From the memory, the data on the shape of the object to be measured and its material, the correspondence between the structural element and its material, the nodes and their coordinate values, the structural element and its connectivity, etc. Structural analysis preprocessing means for creating shape data, and structural analysis of the measurement object from the shape data obtained by the structural analysis preprocessing means and the physical property values stored in the material-physical property value correspondence memory. Stress lines for all the elements that make up the analysis model of the measurement object are automatically created from the structure analysis means, the analysis results obtained by the structure analysis means, and the shape data obtained by the structure analysis preprocessing means. It comprises a stress line automatic creation means, a stress evaluation means for performing stress evaluation on all stress lines obtained by the stress line automatic creation means, and an output means for outputting the evaluation result by the stress evaluation means. A stress evaluation device for a structure according to the ASME standard.