JP2001132900A - Response analysis method and device for piping system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically make an analysis incorporating the shape elements of various piping used for a piping system and an analysis in the plastically deformed condition of the piping. SOLUTION: Data related to load and deformation quantity is previously acquired parameter by parameter related to the rigidity of each of various pipelines used for a piping system, and the data is stored in a load-deformation quantity data base. In actually making a response analysis of the piping system, and analytic model composed of finite elements is prepared by setting the rigidity characteristic of each pipeline in the piping system to be analyzed, according to the load-deformation quantity data read from the load-deformation quantity data base. A response analysis device for that purpose comprises an analysis data input device 26, a data processor 27, an information display device 28, a load-deformation quantity data input device 29 and the load-deformation quantity data base 30, and the data processor 27 comprises an analysis data origination means 27a and a response computing means 27b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a response analysis for evaluating a response when a piping system of various plant facilities receives a load due to an event such as an earthquake, and more particularly, to a shape of each piping used in the piping system. The present invention relates to a response analysis that enables linear analysis to perform analysis that incorporates elements and analysis under conditions where piping is plastic.

[0002]

2. Description of the Related Art When evaluating the response of a piping system of various plant facilities to a load caused by an event such as an earthquake, it is effective to model the piping system using a finite element method and perform a response analysis. is there. When evaluating the overall response of a piping system by finite element analysis, it is necessary to create an analysis model of the entire piping system. It is generally economical to use a beam element for this analysis model from the viewpoint of the amount of work involved in modeling and the cost of calculation by the analysis model. In order to perform modeling using beam elements, generally, a sectional area, a second moment of area, and a second pole moment calculated from the diameter and thickness of a pipe are calculated to define rigidity. However, the actual piping system is composed of pipes of various shapes such as curved pipes and branch pipes in addition to straight pipes, and beam elements cannot precisely model the characteristics of these shapes. on the other hand,
In order to model the characteristics of the pipe shape as described above by the finite element method, a method of modeling the shape in detail using shell elements, solid elements, or the like is conceivable. Alternatively, for example, in the finite element analysis program “ABAQUS” provided by Hibbitt, Karlsson & Sorensen, Inc., a finite element for simulating the deformation behavior of a curved tube can be used, and the manual “ABAQUS / Standard User's M
anual, Volume I, II, Version 5 "(1995). In addition, when the material of the pipe is in the elastic range, a method of considering the shape effect of the pipe by a rigidity correction coefficient called a flexibility factor, for example, ASME Boile
It is proposed in r and Pressure Vessel Code Section III, etc., and is used for seismic design of piping systems in various plant facilities.

[0003] When the material of the pipe is plastic, that is, when a load condition that causes plastic deformation of the pipe is assumed, the relationship between the load acting on the pipe and the amount of deformation is not a linear relation. Therefore, the response evaluation requires a non-linear analysis such as a time history response analysis method by direct integration. Such a non-linear analysis generally requires a larger amount of calculation and a higher calculation cost than a linear analysis. As a simple response evaluation method when the material of the pipe is plastic, there is an example disclosed in, for example, Japanese Patent Application Laid-Open No. H11-211553. This response evaluation method is a method in which a plastic part of a pipe is modeled by a spring element, and the characteristics of a plastic member are expressed by linearly approximated rigidity and damping. This response evaluation method is effective as a simple evaluation method, but in order to apply it,
Depending on the shape and dimensions of the various pipes, the characteristics of each plastic pipe or the data obtained by linearly approximating the properties are used. Although not directly related to the response analysis, there is a technique for designing piping such as disclosed in Japanese Patent Application Laid-Open No. Hei 7-21231, and for monitoring thermal stress of piping, for example, Japanese Patent Application Laid-Open No. Hei 8-15115. There is a technology such as disclosed in US Pat.

[0004]

In the conventional response analysis method as described above, it is difficult to accurately model the shape effects of curved pipes and branch pipes other than straight pipes appearing in an actual piping system. Or, even if it is possible, there is a problem that the amount of work for analysis becomes enormous. In other words, when using an analysis model based on beam elements that requires a relatively small amount of work,
Cross-sectional area of beam element calculated from caliber and wall thickness, cross-section 2
Since rigidity is defined only by the second moment and the second polar moment, it is not possible to model strictly the shape effect. On the other hand, when using a shell element or solid element that enables strict modeling of the shape effect, Requires a huge amount of work. In the case of the conventional response analysis method, the analysis under the condition that the relationship between the load and the deformation amount in the pipe is not a linear relationship due to the plasticity of the pipe material is inevitably a non-linear analysis, and the amount of work is enormous. There is also a problem.

Accordingly, it is an object of the present invention to provide a response analysis apparatus and method which makes it possible to economically perform an analysis incorporating shape elements of each pipe used in a pipe system and an analysis under conditions where the pipe is plastic. It is in.

[0006]

In order to achieve the above object, the present invention provides a piping system response analysis method in which an analysis model of a piping system is created by a finite element method and a response analysis is performed based on the analysis model. The data on the relationship between the load and the deformation amount obtained in advance for each parameter related to the rigidity of various pipes used in the piping system and stored in the load-deformation amount database is used, and the data is read from the load-deformation amount database. An analysis model composed of finite elements is created by setting rigidity characteristics of each pipe in a pipe system to be analyzed based on load-deformation amount data.

In order to achieve the above object, the present invention provides an analysis data input device for inputting load condition data and analysis condition data necessary for creating an analysis model of a piping system by a finite element method; In a response analysis device for a piping system having at least a data processing device for creating an analysis model, data on a relationship between a load and a deformation amount obtained in advance for each stiffness parameter for various types of piping used in the piping system. A load-deformation amount database to be stored is provided, and by using the load-deformation amount data read from the load-deformation amount database together with the data input by the analysis data input device, an analysis model composed of finite elements can be used as the data processing device. Is created.

[0008]

Embodiments of the present invention will be described below. In doing so, the background of the present invention will be described first. In this specification, a piping system means a structure composed of a plurality of pipes having various shapes and a support structure that supports the pipes. FIG. 1 shows an example of a deformed state in a portion where a straight pipe 2 is connected to both ends of a curved pipe 1 as a part of such a piping system. When such a piping system receives a load due to an event such as an earthquake, the curved pipe 1 is deformed like the curved pipe 3. If the amount of deformation exceeds a certain amount, for example, the strain around the portion 4 exceeds the elastic limit of the material and plastically deforms. FIG. 2 shows an example of a stress-strain curve. The material becomes plastic when the stress generated in the pipe exceeds the yield stress 5, which is the elastic limit, and enters the area of the curve 6. When the material of the pipe is plastic, the relationship between the load acting on the pipe and the amount of deformation is no longer linear.

FIG. 3 shows an example of a repetitive load acting on a pipe. In the repetitive load, for example, the time history waveform of the load changes as shown by a curve 7. FIG. 4 shows the relationship between the load on the piping and the amount of deformation when receiving such a repetitive load. The relationship between the amount of deformation and the load when the material of the pipe is plastic becomes a loop as shown by a curve 8, for example. In response evaluation of a piping system, it is necessary to model the relationship between the load and the amount of deformation of each piping forming such a piping system. Here, the load acting on the pipe can be, for example, a bending moment, a torsional moment, an axial force, a shear force, or the like, depending on the deformation direction. Similarly, the deformation amount may be a bending angle, a torsion angle, an axial deformation amount, a shear deformation amount, or the like of the pipe depending on the deformation direction.

FIG. 5 is a diagram schematically showing an example of a piping system. The piping system of various plant facilities is straight pipe 9, curved pipe 1
0, branch pipes 11, reducers 12, and anchors 13 of various shapes, and pipe support structures 14, 1
5 and the like. As you can see from this example,
The piping constituting the piping system includes piping of various shapes, and it is generally difficult to theoretically formulate and model the load-deformation amount relationship for all of them. As a method of considering the effect of the shape, there is a method of modeling the shape of various pipes in detail by a finite element method using solid elements or shell elements. FIG. 6 shows an example of an analysis model using the shell element 16, and FIG. 7 shows an example of an analysis model using the solid element 17. However, modeling an actual piping system composed of various shapes of piping as shown in FIG. 5 with solid elements and shell elements is difficult in consideration of the amount of work required for model creation, calculation cost, and the like. Not efficient. Even if the range to be modeled in detail is limited to the curved pipe 10 and the branch pipe 11 excluding the straight pipe 9, the amount of work and calculation cost spent on model creation are still large. Therefore, it is desired that a model can be modeled by considering only the shape of a curved pipe or a branch pipe using only economical elements such as a beam element and a spring element. In the present invention, this is made possible, and furthermore, an analysis model can be created without using even a beam element or a spring element as an element for the finite element method. An example of an analysis model using the beam element 18 is shown in FIG.
become that way.

FIG. 9 shows an example of an analysis model composed of a beam element and a spring element which is generally used in response analysis of a piping system. Point 19 in the figure represents a node when the target model is divided into finite elements by the finite element method. In this example,
The pipe 20 is modeled by beam elements, and the pipe support structure 2
1 is modeled by a spring element. However, the usage of the beam element and the spring element in the modeling is not limited to this, and for example, it is possible to model a curved pipe portion or a branch pipe portion with a rotary spring element. FIG. 10 shows an example in which a curved pipe portion and a branch pipe portion are modeled by rotary spring elements.
In this example, a spring element is used for modeling the curved tube portion 24 and the branch tube portion 25. In conventional seismic design of piping systems of various plant facilities, when modeling piping systems using beam elements and spring elements, the rigidity correction called flexibility factor is corrected on the condition that the piping material is not plastic. The effect of the shape is simply considered by correcting the rigidity by the coefficient. However, the method using the flexibility factor is a relatively rough approximation, and it cannot be said that high-precision analysis can always be performed.In particular, when the material of the pipe is plastic, the effects of various pipe shapes are formulated, It is generally difficult to reflect on modeling by beam elements or spring elements. On the other hand, according to the present invention, as will be described below, according to the present invention, data on the relationship between the load acting on the pipe and the amount of deformation is obtained in advance by a test or analysis and stored in a database, and finite element Each element modeled by the method (this may be a beam element or a spring element as described above,
(It is not necessary to do so according to the principle of the present invention.) Therefore, the shape effect can be effectively incorporated. Further, even in the case where the material of the pipe is plastic, it is possible to make the data to be made into a database suitable for linear analysis. Therefore, it is possible to perform the analysis effectively incorporating the shape effect by the linear analysis.

FIG. 11 shows a piping system response analyzer according to one embodiment. This response analysis device comprises an analysis data input device 26, a data processing device 27, an information display device 28, a load-deformation amount data input device 29, and a load-deformation amount database 30. 27a and response calculation means 27b.
The analysis data input device 26 includes, for example, coordinate data of the arrangement of the piping system, piping shape data such as the wall thickness and diameter of each pipe and the radius of curvature of a curved pipe, boundary condition data of a fixed part, seismic load, internal pressure load, and the like. Is used to input the load condition data and analysis condition data such as a response analysis method. As the analysis data input device 26, for example, a keyboard or a mouse is used. The analysis data creation means 27a
Create an analysis model and create analysis data for response calculation. The above-mentioned data input by the analysis data input device 26 is used for this processing. In particular, when creating an analysis model, a load-deformation amount database 30 described later is used.
Load-deformation amount data read from is also used. Response calculation means 27b performs response calculation. For this calculation, the analysis data created by the analysis data creation means 27a is used. A computer such as a workstation or a personal computer is used as the data processing device 27 including the analysis data creation unit 27a and the response calculation unit 27b. As the analysis data creating means 27a of the data processing device 27, for example, a commercially available pre / post processor can be used. A finite element analysis program can be used for the response calculation means 27b. The information display means 28 displays data input performed by each device, a process of processing, a result thereof, and the like as necessary. Examples of the information display unit 28 include a screen display on a display and an output by a printer.

The load-deformation amount data input device 29 is used to input the load-deformation amount data to the load-deformation amount database 30, and the load-deformation amount database 30 stores the data. The load-deformation amount data can be obtained, for example, by actually performing a vibration test on a pipe, or by finite element analysis in which the shape is modeled in detail by a solid element or a shell element. It is also conceivable to conduct a literature search or the like and cite the data therefrom.
That is, regardless of the acquisition method, the load-deformation amount data is acquired in advance in a database by classifying based on parameters relating to the rigidity of the pipe such as the shape and dimensions and the internal pressure, and for each pipe, The present invention has a feature in that this is used for analysis. Therefore, such load-deformation amount data can be acquired at any time, and when acquired, the load-deformation amount data input device 29 adds the data to the load-deformation amount database 30 or corrects the existing data. I do. For the load-deformation amount database 30, a data storage device such as a hard disk of a workstation or a personal computer is used. Load-deformation data input device 2
For example, a keyboard, a mouse, and the like are used for 9 as in the case of the analysis data input device 26. Therefore, this load-
The deformation data input device 29 includes the analysis data input device 2.
The same device as 6 may be used. Load-
Information input by the deformation data input device 29 and data of the load-deformation data base 30 can be displayed on the information display means 28 as necessary.

The data stored in the load-deformation amount database 30 will be described below. FIG. 25 shows the load-
A procedure for creating the deformation amount database 30 will be described. Load-
The load-deformation amount data to be converted into a database in the deformation amount database 30 is obtained by the test, the analysis, and the like as described above (step 67 in FIG. 25). As the load and the amount of deformation to be acquired, for example, a bending moment which is the most significant of the loads acting on the pipe and a bending angle which is the amount of deformation due to the bending moment can be considered. FIG. 12 shows an example of a relationship between a bending moment and a bending angle of a partial piping system including a bent pipe.
In this example, a bending moment acts on a piping system including a bent pipe in a plane formed by the bent pipe, thereby generating a bending angle. Similarly, for a straight pipe or a branch pipe other than a curved pipe, the bending moment and the bending angle can be acquired data. In the case of a curved pipe and a branch pipe, a bending moment and a bending angle can be defined for the inside and outside of a plane formed by the bent pipe or the branch pipe, respectively. The load condition such as moment when acquiring such data may be monotonically increased or increased or decreased sinusoidally with respect to time. FIG. 13 shows, as an example, a relationship curve 34 between the moment and the rotation angle for one cycle when a repetitive load is applied to the pipe. FIG. 14 shows an example of the relationship curve 35 when a monotonically increasing load is applied. In the load-deformation amount database 30, the relationship between the load and the deformation amount as in the example shown here is classified based on a parameter relating to the rigidity of the pipe and is made into a database.

[0015] When the load-deformation amount data obtained by the test or the analysis is compiled into a database, the above-mentioned curve can be used as it is. However, in that case, the data amount becomes too large, and often exceeds the normal processing capacity of the analysis data creating means 27a. Therefore, it is appropriate that the curve is approximated by a straight line and expressed as a numerical value to make a database (step 68 in FIG. 25). Hereinafter, this will be described. FIG. 15 shows a load-deformation amount relationship curve 35 obtained under a monotonic load condition.
Here, an example in which is approximated by a straight line and expressed as a numerical value is shown. The load-deformation amount relationship curve 35 obtained by the test or analysis is approximated by, for example, two straight lines including a straight line 36 and a straight line 37. In this case, line 3
6 is the rigidity Ke, the straight line 37 is the rigidity Kp, and these 2
The boundary of the straight line can be expressed numerically as a moment Mp38. Alternatively, as shown in FIG.
The rigidity Kp is set to 0, and a so-called perfect elastic-plastic type two straight line 39
And 40 may be approximated. In this case, the elastic rigidity Ke
And the plastic moment Mp41. Similarly, the load-deformation amount relationship obtained under the load condition of the repetitive mold can be a linear approximation including a perfect elastoplastic mold. FIG.
Shows an example in which a curve is linearly approximated. In this case, similarly to the case of the monotonic load, the load-deformation curve 34 obtained by the test or the analysis includes a straight line 42 defined by the elastic rigidity Ke, a straight line 43 defined by the rigidity Kp after plasticity, and A numerical value can be approximately expressed by the plastic moment Mp44. Such an approximation method using straight lines is not limited to two straight lines, but an approximation method using multiple straight lines is also possible. In addition to the approximation method using a polyline, an approximation method using a smooth curve is also possible.
As a method of defining such a loop shape, for example, Wen
Methods such as the model and the Ramberg-Osgood model have been proposed and can be used. In this case, some parameters defining the loop shape are stored in a database.

The load-deformation amount data as described above is input to the load-deformation amount database 30 by the load-deformation amount data input device 29 (step 69 in FIG. 25).
However, the load-deformation amount data of a pipe differs depending on parameters related to the rigidity of the pipe such as the shape and dimensions of the pipe. Therefore, it is necessary to classify the database of the load-deformation amount data of the piping based on these parameters. Examples of parameters for classification are shown below. (1) Piping shape (2) Diameter (3) Wall thickness (4) Curvature radius for curved pipes (5) For branch pipes, diameter ratio between mother pipe and branch pipe (6) Internal pressure Among them, parameters (2) to (5) are parameters related to dimensions, and generally speaking, parameters relating to the rigidity of the pipe mainly include shape, dimensions, and internal pressure. However, specific individual parameters are not limited to the above, and parameters as needed can be used. It is also effective to express the numerical data such as the diameter and thickness of the pipe without using a database as it is, and to express it in a dimensionless amount such as the ratio of diameter to thickness. further,
In order to understand the basis of the data, it is necessary to distinguish between analysis and testing.
In the case of analysis, an analysis date and time, an analysis method, an analysis program, and the like may be recorded. 18 to FIG.
Some examples of the deformation amount database are shown.

FIG. 18 is an example of a database when the pipe shape is a straight pipe. In this example, the pipe shape 45, diameter 46, wall thickness 47, ratio of diameter to wall thickness 48, and internal pressure 49 are used as the pipe parameters. For these parameters, the contents of the database are a yield moment 50 and a secondary rigidity 51. FIG. 19 shows an example of a curved tube database. In the case of a curved pipe, an item of a radius of curvature 52 is added as compared with a straight pipe. In FIG.
3 shows an example of a branch pipe database. In the case of a branch pipe, for example, the mother pipe 53 and the branch pipe 54 are distinguished, and the diameters 46a and 46b and the wall thicknesses 47a and 47b are used as parameters. Further, it is conceivable to use the diameter ratio 55 between the mother pipe and the branch pipe as a parameter. These databases are examples in the case of two-line approximation, but in the case of multi-line approximation, a database of moments and stiffness is created according to the number of straight lines. When a loop shape is approximated by a Wen model or a Ramberg-Osgood model, numerical values of parameters defining each loop shape are stored in a database.
For using such database data,
Even when the parameters of the target pipe do not always match the values stored in the database, the data to be obtained can be easily obtained by interpolation or extrapolation.

The load-deformation data for each type of piping, which is made into a database as described above, is used to model the elastic characteristic or the elasto-plastic characteristic of each piping in the piping system to be analyzed. The response analysis can be performed based on the analysis model obtained by the above. The response analysis is a linear analysis if the pipe is not plastic, and a non-linear analysis if the pipe is plastic. A typical example of a nonlinear response analysis method is a time history response analysis method using direct integration.

However, the non-linear analysis generally requires a large calculation cost. On the other hand, if the analysis model is linear, response analysis can be performed by more economical linear analysis. Therefore, in the present invention, the linear response analysis can be performed even under the condition that the piping is plastic by utilizing the principle of the present invention that uses the data obtained in advance and made into a database as described above. For this purpose, the present invention uses a method of linearly approximating the load-deformation amount relationship in which the material of the pipe is plastic and non-linear and is modeled by linear rigidity and linear damping. Typical examples of the linear response analysis method include a modal time history response analysis method using modal analysis, a modal response spectrum analysis method, and the like. An approximation method based on linearization will be described with reference to FIG. Curve 56 shows the load-deformation relationship after plasticity obtained by a test or analysis. The rigidity after plasticity is lower than the rigidity Ke of the straight line 57 representing the load-deformation amount relationship in the elastic region. Further, the load-deformation amount relationship forms a loop as shown by a curve 56. Energy Δ represented by the area of the portion 58 surrounded by this loop
E is dissipated every cycle due to plastic deformation of the tubing, which results in increased damping. Therefore, it is possible to approximate the elasto-plastic characteristic by the linear rigidity with reduced elastic rigidity and the linear damping with increased elastic region damping.

An example of a method for setting rigidity and damping for approximating the elasto-plastic characteristic will be described. Methods for calculating the approximate linearized rigidity include, for example, the following method. Rigidity calculation method 1: A method in which the slope is defined as the slope between the maximum deformation points of the load-deformation amount relationship constituting the loop or the straight line connecting one of the maximum deformation points and the origin. Stiffness calculation method 2: A method of calculating the stiffness Keq by Equation 1. This method of calculating the stiffness is generally called Caughey's method.

(Equation 1) Here, X is the maximum deformation amount, and F is a function representing the loop shape. FIG. 21 shows an example in which the loop curve 56 is approximated by a straight line 59 connecting the maximum deformation points. Similarly, for example, there is the following method. Damping calculation method 1: Dissipated energy per cycle Δ from the area surrounded by the load-deformation-related loop curve
E is obtained, and the damping ratio heq of the pipe is derived from Expression 2.

(Equation 2) Here, h represents the damping ratio of the elastic region. Attenuation calculation method 2: A method of calculating the attenuation ratio Keq by Equation 3. This method is generally called Caughey's method.

(Equation 3) Here, Ke represents the rigidity of the elastic region. In the examples so far,
A method for directly deriving linear stiffness and linear damping from the load-deformation amount relationship curve obtained in the test and analysis was shown. In addition to this method, it is also possible to first approximate the curve relating to the load-deformation amount with a polyline, and indirectly set the linear rigidity and the linear damping from the moment and the rigidity defining the polyline. In the following, when the curve of the load-deformation amount relationship is approximated by two straight lines and expressed by the yield moment Mp and the secondary rigidity Kp,
An example of a calculation formula for evaluating the stiffness Keq and the damping ratio heq that are linearly approximated by the above-described stiffness calculation method 1 and damping calculation method 1 will be described.

(Equation 4)

(Equation 5) The linear approximation method as described above is generally called an equivalent linearization method. The rigidity and damping derived by this equivalent linearization method are called equivalent rigidity and equivalent damping.

FIG. 22 shows an example of a response analyzer for performing linear approximation. This response analyzer is basically the same as the response analyzer of FIG. 11, and includes an analysis data input device 26, an analysis data creation unit 27a, and a response calculation unit 27b.
11 is provided with a data processing device 27 and an information display device 28, which are different from the response analysis device of FIG.
The load-deformation amount data input device 29 and the load-deformation amount database 30 in the response analysis device 1 are replaced with a linear rigidity / linear damping data input device 60 and a linear rigidity / linear damping database 61, respectively. In other words, the difference is that data replaced with linear rigidity and linear damping in advance is used as load-deformation amount data for creating a database under conditions where the material is plastic.

The linear stiffness / linear damping database 61 is a database of linear stiffness / linear damping data derived by the method described above. The data of the linear stiffness / linear damping database 61 is added or modified by the linear stiffness / linear damping data input device 60. Such data of the linear rigidity / linear damping database 61 and the analysis data input device 2
6 using the data input in step 6
7a creates a linear analysis model and analysis data for response calculation. Then, a linear response calculation is performed by the response calculation means 27b. As the linear rigidity / linear damping database 61, a data storage device such as a hard disk of a workstation or a personal computer is used.
As the linear rigidity / linear damping data input device 60, for example, a keyboard, a mouse, or the like is used. This linear stiffness
The linear decay data input device 60 is the analysis data input device 2
6 may be used. Further, it is desirable that input information from the linear stiffness / linear attenuation data input device 60 and data of the linear stiffness / linear attenuation database 61 be displayed on the information display means 28 as necessary.
FIG. 26 summarizes the procedure for creating the linear rigidity / linear damping database 61.

FIG. 23 shows an example of the linear stiffness / linear damping database 61. In this example, the equivalent rigidity 62 and the equivalent damping 63 are stored in a database. The equivalent rigidity and the equivalent damping are, as shown in FIG.
Therefore, the equivalent rigidity and the equivalent damping are evaluated in correspondence with the maximum deformation amount. In this case, a database may be directly associated with the maximum deformation amount such as the bending angle or the axial deformation amount of the pipe. In the example of FIG. 23, a database is created using a dimensionless quantity 64 called a plasticity factor. The plasticity is defined as the ratio of the maximum deformation amount to the deformation amount 66 when yielding. As described above, an example of the linear stiffness / linear damping database has been described. However, even when the parameters of the target piping do not match the values stored in the database, the data to be obtained can be easily obtained by interpolation or extrapolation. I can do it. According to the method described above, it is possible to create a linear analysis model and perform a linear analysis.

[0024]

According to the present invention, a piping analysis model for response evaluation in piping design can be created so as to enable accurate and economical response analysis, and the response analysis is performed using this model. In addition, the response of the pipe can be predicted efficiently.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a modification of a pipe.

FIG. 2 is an explanatory diagram illustrating an example of a stress-strain relationship of a pipe.

FIG. 3 is an explanatory diagram of an example of a repetitive load history acting on a pipe.

FIG. 4 is an explanatory diagram of an example of a relationship between a repetitive load acting on a pipe and an amount of deformation.

FIG. 5 is an explanatory diagram of an example of a piping system including various shapes of piping and a piping support structure.

FIG. 6 is an explanatory diagram of an example of an analysis model of a pipe using a shell element.

FIG. 7 is an explanatory diagram of an example of a pipe analysis model using solid elements.

FIG. 8 is an explanatory diagram illustrating an example of an analysis model of a pipe using a beam element.

FIG. 9 is an explanatory diagram illustrating an example of an analysis model of a piping system including a beam element and a spring element.

FIG. 10 is an explanatory diagram illustrating an example of an analysis model of a piping system in which a curved pipe portion and a branch pipe portion are modeled by rotary spring elements.

FIG. 11 is a configuration diagram of a piping system response analysis apparatus according to an embodiment of the present invention.

FIG. 12 is an explanatory diagram of an example of a deformed state of a curved tube.

FIG. 13 is an explanatory diagram illustrating an example of a relationship between a moment load and a rotation angle of a repetitive mold.

FIG. 14 is an explanatory diagram of an example of a relationship between a monotonically increasing moment load and a rotation angle.

FIG. 15 is an explanatory diagram of an example in which a curve representing the relationship between a monotonically increasing moment load and a rotation angle is approximated by a straight line.

FIG. 16 is an explanatory diagram of an example in which a curve representing a relationship between a monotonically increasing moment load and a rotation angle is approximated by two straight lines including a straight line having a slope of 0;

FIG. 17 is an explanatory diagram of an example in which a curve representing a relationship between a repetitive moment load and a rotation angle is approximated by a straight line.

FIG. 18 is an explanatory diagram of a content example of a load-deformation amount database of a straight pipe portion.

FIG. 19 is an explanatory diagram of a content example of a load-deformation amount database of a curved pipe portion.

FIG. 20 is an explanatory diagram of a content example of a load-deformation amount database of a branch pipe portion.

FIG. 21 is an explanatory diagram of an example in which a curve representing a relationship between a moment load and a rotation angle is linearly approximated.

FIG. 22 is a configuration diagram of a piping system response analyzer according to another embodiment of the present invention.

FIG. 23 is an explanatory diagram of a content example of a linear rigidity / linear damping database.

FIG. 24 is an explanatory diagram of an example of a maximum deformation amount and a linearly approximated straight line.

FIG. 25 is an explanatory diagram of an example of a procedure for creating a load-deformation amount database.

FIG. 26 is an explanatory diagram of an example of a procedure for creating a load-deformation amount database when linear approximation is performed using linear rigidity and linear damping.

[Explanation of symbols]

 Reference Signs List 9 straight pipe 10 curved pipe 11 branch pipe 12 reducer 13 nozzle 14 pipe support structure 15 pipe support structure 16 shell element 17 solid element 18 beam element 19 node 20 beam element 21 (translational) spring element 24 rotary spring element

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoru Ono 3-1-1 Sachimachi, Hitachi-shi, Ibaraki F-term in the Nuclear Power Division, Hitachi, Ltd. (Reference) 3J071 BB01 CC11 DD13 EE07 EE19 EE29 FF04 FF16 5B046 AA02 DA01 DA02 GA01 GA02 JA07 KA05

Claims (4)

[Claims] In a response analysis method for a piping system in which an analysis model of a piping system is created by a finite element method and a response analysis is performed based on the analysis model, a parameter relating to rigidity of various piping used in the piping system is set in advance. The data of the relationship between the load and the deformation amount acquired and stored in the load-deformation amount database shall be used, and the load-deformation amount data read from this load-deformation amount database will be used to analyze each pipe in the piping system to be analyzed. A response analysis method for a piping system, wherein an analysis model including finite elements is created by setting rigidity characteristics. 2. When an analysis is performed under the condition that a pipe is plastic, data obtained by replacing the relationship between load and deformation with linear rigidity and linear damping is used as data to be stored in the load-deformation database. 2. The response analysis method for a piping system according to claim 1, wherein the linear analysis can be performed by the following. 3. An analysis data input device for inputting load condition data and analysis condition data required for creating an analysis model of a piping system by a finite element method, and a data processing device for creating the analysis model In a response analysis device for a piping system having at least a load-deformation amount database for storing data of a relationship between a load and a deformation amount obtained in advance for each stiffness parameter for various types of piping used in the piping system, By using the load-deformation amount data read from the load-deformation amount database together with the data input by the analysis data input device, the data processing device creates an analysis model including finite elements. Characteristic piping system response analyzer. 4. When the analysis is performed under the condition that the pipe is plastic, data obtained by replacing the relationship between the load and the deformation with linear rigidity and linear damping is used as the data to be stored in the load-deformation database. Item 4. A response analysis device for a piping system according to item 3.