A pipeline mechanics calculation method and device

Abstract

This invention provides a method and apparatus for calculating pipeline mechanics. The method includes: generating a pipeline beam model composed of multiple pipeline beam elements connected together based on the parameter information of each component in the pipeline to be calculated; obtaining the start and end nodes and mesh generation information of the target shell component to be analyzed in detail; generating a target shell component mesh model formed by splicing multiple shell elements; replacing the pipeline beam elements at corresponding positions in the pipeline beam model with the target shell component mesh model to form a hybrid model; performing finite element calculations on the hybrid model to obtain the displacements of each node in the hybrid model; calculating the nodal internal forces of the pipeline beam elements based on the nodal displacements of the pipeline beam elements; calculating the stress of each shell element based on the mesh node displacements of the target shell component mesh model; and calculating the stress of the pipeline beam elements based on the nodal internal forces of the pipeline beam elements. This invention can complete the calculation and evaluation of pipelines and shell components in one step, greatly improving the efficiency and accuracy of pipeline design.

Description

Technical Field

[0001] This invention relates to the field of pipeline design technology, and specifically to a pipeline mechanics calculation method and apparatus. Background Technology

[0002] Current piping calculation software typically uses one-dimensional pipe beam elements for model calculations, including straight and curved pipe beam elements, all of which are line elements. Furthermore, piping and equipment calculations are usually performed separately: first, the piping calculation is performed to obtain the thrust exerted by the pipe on the equipment, then load combination calculations are performed, and finally, the combined loads are used to perform stress analysis and evaluation on the equipment. Some programs can use shell elements for calculating special components. However, the methods for creating shell element components are quite complex. Some require inputting node coordinates node by node and providing a detailed description of each shell element. Others require using a separate modeling module to create the shell element model, and then the main program converts this shell element component into a stiffness matrix, which is then input into the piping model for calculation. In this calculation, the shell element model only provides the displacement and internal forces at the two connection points. After obtaining the piping solution, the forces on the component are then applied to the equipment for separate calculation of the shell element component. Therefore, the inability of existing piping calculation software to easily create shell element components is a major technical problem.

[0003] The method of directly placing shell element component models into piping problems is theoretically sound. Most common finite element programs can do this, but the problem lies in extremely low efficiency. This includes issues such as modeling efficiency, connection techniques between pipes and shell components, compliance with specifications during the process, and implementation of specifications during evaluation. These problems are why general-purpose finite element software cannot meet the needs of engineering design calculation and analysis applications. The technologies involved include: user interaction, or the definition of piping description methods, piping program calculations (including support requirements for standard constraints, calculation methods for specification requirements and the correspondence between pipe loads), modeling methods for pipe components (such as tees), and the correspondence between pipe elements and shell elements. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a pipeline mechanics calculation method and device that can complete the calculation and evaluation of pipelines and shell components in one go, thereby greatly improving the efficiency of pipeline design.

[0005] The technical solution adopted to solve the technical problem of this invention is:

[0006] This invention provides a method for calculating pipeline mechanics, comprising:

[0007] Based on the parameter information of each component in the pipeline to be calculated, a pipeline beam model composed of multiple pipeline beam elements is generated, along with the node information of each pipeline beam element. There is a one-to-one correspondence between components and pipeline beam elements.

[0008] Obtain the start and end node information and mesh generation information of the target shell component that needs detailed analysis, generate a target shell component mesh model formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model.

[0009] The pipe beam elements at corresponding positions in the pipe beam model are replaced with the target shell component mesh model to form a hybrid model.

[0010] Based on the operating conditions of the pipeline and the parameter information of each component, finite element analysis is performed on the hybrid model to obtain the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the nodal internal forces of the pipeline beam elements are calculated. Based on the mesh node displacements of the target shell component mesh model, the stresses of each shell element are calculated.

[0011] Calculate the stress of the pipe beam element based on the nodal internal forces of the pipe beam element.

[0012] Optionally, it further includes: determining the material density of the target shell component based on the linear density of the target shell component, and replacing the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component.

[0013] Optionally, determining the material density of the target shell component based on its linear density specifically includes:

[0014] Based on the linear density w of the target shell component, its original material density w′ is determined using the formula: w′=w / g / t, where, after the target shell component is circumferentially segmented, the end face circle forms N arcs, g is the length of the arc, g=πD / N, t is the wall thickness of the target shell component, and D is the pipe diameter of the target shell component.

[0015] Based on the number of circumferential segments of the target shell component, its circumferential reduced density coefficient fac is calculated. The calculation formula is: fac=g / g′, where g′ is the length of the broken line segment corresponding to the arc after circumferential segmentation of the target shell component, g′=2D×sin(180 / N).

[0016] Then calculate the material density w″ of the target shell component according to the following formula:

[0017] w″=w′×fac.

[0018] Optionally, the nodes of the pipe beam elements at the connection between the target shell component mesh model and the pipe beam elements are designated as master nodes, and the nodes of the target shell component mesh model corresponding to the master nodes at the connection between the target shell component mesh model and the pipe beam elements are designated as slave nodes.

[0019] Finite element analysis was performed on the hybrid model to obtain the displacements of each node, including: at the connection between the target shell component mesh model and the pipe beam element, only the displacements of the main nodes were calculated.

[0020] The step of calculating the stress of each shell element based on the mesh node displacements of the target shell component mesh model specifically includes:

[0021] Based on the displacement of the master node, calculate the displacement of each slave node corresponding to the master node.

[0022] The displacements of each slave node, along with the displacements of other mesh nodes in the target shell component mesh model obtained from the finite element calculation, constitute the mesh node displacements of the target shell component mesh model.

[0023] The stress of each shell element is calculated based on the mesh node displacements of the target shell component mesh model.

[0024] Optionally, before calculating the displacements of each slave node corresponding to the master node based on the displacement of the master node, the method further includes: determining whether the operating condition is a non-temperature operating condition or a temperature operating condition.

[0025] If the operating condition is determined to be a non-temperature operating condition, the displacement of each slave node corresponding to the master node is calculated using equation (2) based on the displacement of the master node:

[0026] d′=d×a (2)

[0027] Where d is the displacement of the master node, d′ is the displacement of the slave node corresponding to the master node, and a is the transformation matrix that converts the displacement of the master node to the displacement of the slave node.

[0028] If the operating condition is determined to be a temperature-related condition, the displacement of each slave node corresponding to the master node is calculated using equation (3) based on the displacement of the master node:

[0029] d′=d×(a×(1+alf)) (3)

[0030] Where alf is the coefficient of thermal expansion of the pipe material.

[0031] The present invention also provides a pipe mechanics calculation device, comprising:

[0032] The pipe beam generation module is used to generate a pipe beam model composed of multiple pipe beam elements connected together, based on the parameter information of each component in the pipe to be calculated, as well as the node information of each pipe beam element. There is a one-to-one correspondence between components and pipe beam elements.

[0033] The shell generation module is used to obtain the start and end node information and mesh generation information of the target shell component that needs to be analyzed in detail, generate a mesh model of the target shell component formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model.

[0034] The replacement module is used to replace the pipe beam elements at corresponding positions in the pipe beam model with the target shell component mesh model to form a hybrid model.

[0035] The finite element method (FEM) module is used to perform FEM calculations on the hybrid model based on the operating conditions of the pipeline and the parameter information of each component. This yields the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the module calculates the nodal internal forces of the pipeline beam elements. Based on the mesh node displacements of the target shell component mesh model, the module calculates the stresses of each shell element.

[0036] The stress calculation module calculates the stress of the pipe beam element based on the nodal internal forces of the pipe beam element.

[0037] Optionally, it also includes an interface module for receiving the operating condition information of the pipeline to be calculated and the parameter information of each component, and transmitting them to the pipeline beam generation module and the finite element calculation module.

[0038] It is also used to receive the target shell component's numbering information and mesh generation information and transmit them to the shell generation module.

[0039] Optionally, it also includes a shell parameter forming module, which is electrically connected to the interface module, for determining the material density of the target shell component based on the linear density of the target shell component, and replacing the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component.

[0040] Optionally, the shell parameter forming module includes a material density calculation module and a shell parameter updating module. The material density calculation module is electrically connected to the interface module and is used to determine the material density of the target shell component based on its linear density. The shell parameter updating module is electrically connected to the material density calculation module and is used to replace the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component.

[0041] The material density calculation module determines the material density of the target shell component based on its linear density, specifically including:

[0042] Based on the linear density w of the target shell component, its original material density w′ is determined using the formula: w′=w / g / t, where, after the target shell component is circumferentially segmented, the end face circle forms N arcs, g is the length of the arc, g=πD / N, t is the wall thickness of the target shell component, and D is the pipe diameter of the target shell component.

[0043] Based on the number of circumferential segments of the target shell component, its circumferential reduced density coefficient fac is calculated. The calculation formula is: fac=g / g′, where g′ is the length of the broken line segment corresponding to the arc after circumferential segmentation of the target shell component, g′=2D×sin(180 / N).

[0044] Then calculate the material density w″ of the target shell component according to the following formula:

[0045] w″=w′×fac.

[0046] Optionally, the nodes of the pipe beam elements at the connection between the target shell component mesh model and the pipe beam elements are designated as master nodes, and the nodes of the target shell component mesh model corresponding to the master nodes at the connection between the target shell component mesh model and the pipe beam elements are designated as slave nodes.

[0047] The finite element calculation module includes a total nodal displacement calculation module, a mesh nodal displacement generation module, a beam element internal force calculation module, and a shell element stress calculation module.

[0048] The total node displacement calculation module is used to perform finite element calculations on the hybrid model to obtain the displacements of each node in the hybrid model. This includes calculating the displacements of only the main nodes at the connection points between the target shell component mesh model and the pipe beam elements.

[0049] The mesh node displacement forming module is electrically connected to the total node displacement calculation module. It is used to calculate the displacements of each slave node corresponding to the master node based on the master node's displacement. It is also used to summarize the displacements of each slave node, along with the other mesh node displacements of the target shell component mesh model obtained from the finite element calculation, to constitute the mesh node displacements of the target shell component mesh model.

[0050] The beam element internal force calculation module is electrically connected to the total nodal displacement calculation module, and is used to calculate the nodal internal forces of the pipe beam element based on the nodal displacements of the pipe beam element.

[0051] The shell element stress calculation module is electrically connected to the mesh node displacement forming module and is used to calculate the stress of each shell element based on the mesh node displacement of the target shell component mesh model.

[0052] Optionally, the finite element calculation module further includes a judgment module, which is electrically connected between the interface module and the mesh node displacement forming module, and is used to determine whether the working condition is a non-temperature working condition or a temperature working condition.

[0053] If the operating condition is determined to be a non-temperature operating condition, the mesh node displacement generation module is triggered to calculate the displacement of each slave node corresponding to the master node using equation (2) based on the displacement of the master node:

[0054] d′=d×a (2)

[0055] Where d is the displacement of the master node, d′ is the displacement of the slave node corresponding to the master node, and a is the transformation matrix that converts the displacement of the master node to the displacement of the slave node.

[0056] If the operating condition is determined to be a temperature-related condition, the mesh node displacement generation module is triggered to calculate the displacement of each slave node corresponding to the master node using equation (3) based on the displacement of the master node:

[0057] d′=d×(a×(1+alf))

[0058] Where alf is the coefficient of thermal expansion of the pipe material.

[0059] Optionally, the mesh node displacement forming module includes a shell slave node displacement calculation module and a shell node displacement summarization module.

[0060] The shell slave node displacement calculation module is electrically connected to the master node displacement calculation module, and is used to calculate the displacement of each slave node corresponding to the master node based on the displacement of the master node.

[0061] The shell node displacement summarization module is electrically connected to the shell slave node displacement calculation module and the total node displacement calculation module, respectively. It is used to summarize the displacements of each slave node and the other mesh node displacements of the target shell component mesh model obtained in the finite element calculation to form the mesh node displacements of the target shell component mesh model.

[0062] In this invention, for components requiring detailed mechanical analysis, a finite element mesh model is generated (after meshing, every four adjacent nodes constitute a shell element) to replace the corresponding pipe beam elements in the pipe beam model. Finite element calculations are then performed on the resulting hybrid model to obtain the displacements of each node. Based on the nodal displacements of the beam elements in the hybrid model, the nodal internal forces of the pipe beam elements can be calculated, followed by the stresses of the pipe beam elements. Finally, based on the nodal displacements of the target shell component mesh model, the internal forces (i.e., stresses) of each shell element can be calculated. Thus, this invention completes the calculation and evaluation of both the pipe beam elements and the shell components in one step, eliminating unnecessary conservative combination processes and significantly improving the efficiency of pipe design. Furthermore, compared to methods using one-dimensional pipe beam elements for model calculation, the calculation accuracy of this invention is greatly improved. Attached Figure Description

[0063] Figure 1 This is a flowchart of the pipeline mechanics calculation method provided in Embodiment 1 of the present invention;

[0064] Figure 2 A comparison diagram of a smooth cross-section of a pipe and a segmented polygonal line of a shell element;

[0065] Figure 3 A schematic diagram of the master-slave nodes at the connection surface between the tube beam element and the shell element;

[0066] Figure 4 This is a block diagram of the pipeline mechanics calculation device provided in Embodiment 2 of the present invention;

[0067] Figure 5 A pipeline model diagram created for a standard pipeline procedure;

[0068] Figure 6 This is a standard for evaluating the calculated stress of beams;

[0069] Figure 7 A pipe model diagram of a shelled component created for the pipe program of this invention;

[0070] Figure 8 For the pipeline program calculation of this invention Figure 7 The deformation results of the pipeline model under its own weight;

[0071] Figure 9 This is a standard for evaluating the calculated stress of the shell. Detailed Implementation

[0072] The technical solutions of the invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without creative effort are within the scope of the invention.

[0073] In the description of this invention, it should be noted that the use of terms such as "above" to indicate orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings and is only for the purpose of facilitating and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0074] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0075] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "setting," "installation," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0076] This invention provides a method for calculating pipeline mechanics, comprising:

[0077] Based on the parameter information of each component in the pipeline to be calculated, a pipeline beam model composed of multiple pipeline beam elements is generated, along with the node information of each pipeline beam element. There is a one-to-one correspondence between components and pipeline beam elements.

[0078] Obtain the start and end node information and mesh generation information of the target shell component that needs detailed analysis, generate a target shell component mesh model formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model.

[0079] The target shell component mesh model is used to replace the corresponding pipe beam elements in the pipe beam model to form a hybrid model.

[0080] Based on the operating conditions of the pipeline and the parameter information of each component, finite element analysis is performed on the hybrid model to obtain the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the nodal internal forces of the pipeline beam elements are calculated. Based on the mesh node displacements of the target shell component mesh model, the stresses of each shell element are calculated.

[0081] Calculate the stress of the pipe beam element based on the nodal internal forces of the pipe beam element.

[0082] The present invention also provides a pipe mechanics calculation device, comprising:

[0083] The pipe beam generation module is used to generate a pipe beam model composed of multiple pipe beam elements connected together, based on the parameter information of each component in the pipe to be calculated, as well as the node information of each pipe beam element. There is a one-to-one correspondence between components and pipe beam elements.

[0084] The shell generation module is used to obtain the start and end node information and mesh generation information of the target shell component that needs to be analyzed in detail, generate a mesh model of the target shell component formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model.

[0085] The replacement module is used to replace the pipe beam elements at corresponding positions in the pipe beam model with the target shell component mesh model to form a hybrid model.

[0086] The finite element method (FEM) module is used to perform FEM calculations on the hybrid model based on the operating conditions of the pipeline and the parameter information of each component. This yields the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the module calculates the nodal internal forces of the pipeline beam elements. Based on the mesh node displacements of the target shell component mesh model, the module calculates the stresses of each shell element.

[0087] The stress calculation module calculates the stress of the pipe beam element based on the nodal internal forces of the pipe beam element.

[0088] Example 1:

[0089] like Figure 1 As shown, this embodiment provides a method for calculating pipeline mechanics, including:

[0090] Based on the parameter information of each component in the pipeline to be calculated, a pipeline beam model composed of multiple pipeline beam elements is generated, along with the node information of each pipeline beam element. There is a one-to-one correspondence between components and pipeline beam elements.

[0091] Obtain the start and end node information and mesh generation information of the target shell component that needs detailed analysis, generate a target shell component mesh model formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model.

[0092] The pipe beam elements at corresponding positions in the pipe beam model are replaced with the target shell component mesh model to form a hybrid model.

[0093] Based on the operating conditions of the pipeline and the parameter information of each component, finite element analysis is performed on the hybrid model to obtain the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the nodal internal forces of the pipeline beam elements are calculated. Based on the mesh node displacements of the target shell component mesh model, the stresses of each shell element are calculated.

[0094] Calculate the stress of the pipe beam element based on the nodal internal forces of the pipe beam element.

[0095] In engineering design, whether it's a nuclear power plant, thermal power plant, or petrochemical project, there are typically numerous pipelines. The analysis and calculation of these pipelines constitute a significant portion of the plant design work. Computer software is needed to perform mechanical analysis and calculations on the pipeline layout to prove the rationality of the design. This invention is one of several processes within a computer program algorithm for pipeline calculation. Previous pipeline programs mostly used one-dimensional beam elements to simulate pipelines, including straight pipe beam elements and curved pipe beam elements, all of which are line elements. This invention addresses the technical means required to convert line pipeline elements into a three-dimensional shell element model, meeting the requirements of finite element calculations for hybrid models of pipeline beams and shell element components.

[0096] Specifically, for components in pipeline problems requiring detailed mechanical analysis and calculation (i.e., the target shell components mentioned in this invention), a finite element mesh model is generated (after meshing, every four adjacent nodes are connected end-to-end to form a shell element) to replace the corresponding pipe beam elements in the pipe beam model. Finite element calculations are then performed on the resulting hybrid model to obtain the displacements of each node in the hybrid model. Based on the nodal displacements of the beam elements in the hybrid model, the nodal internal forces of the pipe beam elements can be calculated, followed by the stresses of the pipe beam elements. Based on the nodal displacements of the target shell component mesh model, the internal forces (i.e., stresses) of each shell element can be calculated. Thus, this invention completes the calculation and evaluation of both the pipe beam elements and the shell components in one step, eliminating unnecessary conservative combination processes and significantly improving the efficiency of pipeline design. Furthermore, compared to methods using one-dimensional pipe beam elements for model calculation, the calculation accuracy of this invention is greatly improved.

[0097] To address the weaknesses commonly found in current pipeline calculation programs, this invention proposes the aforementioned pipeline mechanics calculation method. By adding simple input requirements to the existing pipeline calculation problem data, the pipeline program automatically converts one-dimensional beam elements (note: although they are one-dimensional line elements, they actually describe a cylindrical pipe with a diameter; the pipe is the side surface of this cylinder) into a three-dimensional shell element model. Originally, beam elements had only two or a few nodes; after conversion, they may have hundreds or thousands of nodes. Every four adjacent nodes are connected end-to-end to form a shell element, and multiple shell elements are pieced together to form a three-dimensional shell element model. The process of discretizing a smooth cylindrical pipe into a finite number of three-dimensional shell elements is a pre-processing mesh generation technique used in finite element programs, a well-known technique in this field. The end of a beam element is a node, and the end of a shell element is a surface composed of multiple nodes; the technique of associating a point with a surface composed of multiple points is also well-known in this field. This invention integrates these techniques into the modeling module of the pipeline calculation program. The model automatically built using this method can simultaneously and automatically complete the calculation of both the pipeline beam elements and shell elements during the pipeline calculation process. To achieve this functionality, the program structure needs to meet the functional requirements of various elements, including the calculation requirements for pipe and shell elements. This includes methods for handling pipe beams and their connection to shell components, as well as precise methods for converting components in pipes into shell elements to perform mass density conversions.

[0098] In this embodiment, the method further includes: determining the material density of the target shell component based on the linear density of the target shell component, and replacing the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component.

[0099] In this embodiment, determining the material density of the target shell component based on its linear density specifically includes:

[0100] Based on the linear density w of the target shell component, its original material density w′ is determined using the formula: w′=w / g / t, where, after the target shell component is circumferentially segmented, the end face circle forms N arcs, g is the length of the arc, g=πD / N, t is the wall thickness of the target shell component, and D is the pipe diameter of the target shell component.

[0101] Based on the number of circumferential segments of the target shell component, its circumferential reduced density coefficient fac is calculated. The calculation formula is: fac=g / g′, where g′ is the length of the broken line segment corresponding to the arc after circumferential segmentation of the target shell component, g′=2D×sin(180 / N).

[0102] Then calculate the material density w″ of the target shell component according to the following formula:

[0103] w″=w′×fac.

[0104] When converting a pipe model into a shell element, the material density of the target shell component needs to be determined. For pipe models, all commercially available programs require the linear density of the pipe to be given, which includes the material weight of the pipe, typically steel, the working medium, and the insulation material. However, the calculation for shell elements is different. It requires the material density of the target shell component. When calculating weight, the program usually multiplies the shell's area by its thickness and then by its material density to obtain the weight of the shell element.

[0105] When calculating the material density of a target shell component based on the linear weight provided by the pipe, the common algorithm is to divide the linear density per unit length by the pipe circumference and pipe thickness to obtain the material density of the target shell component. The problem with this approach is that the result is not accurate enough, especially when the number of segments is small, which can lead to significant errors. The applicant proposes the solution of this invention:

[0106] Pipe cross-section as Figure 2 As shown: The circle in the figure is a schematic diagram of the pipe's mid-surface. The pipe's wall thickness is ignored here, and the mid-surface radius is R. The figure below shows the pipe divided into six segments along its circumference. The length L is one side length of the shell element, which is the length of the segmented polygonal line.

[0107] If a circular pipe is divided into six segments along its circumference, 360 / 6 = 60, and α = 60 degrees per segment. As shown in the diagram, the length of a broken line segment g′ in the actual pipe is less than the corresponding arc length g. The arc length g = 2 × R × π × 60 / 360 = R × π / 3. The broken line length g′ = R × sin(30) × 2 = R. The ratio of the arc length to the broken line length is π / 3 = 1.047198. Extending this to any number of circumferential segments, the algorithm for converting the linear density w of a given pipe into the material density of a straight pipe is:

[0108] The equivalent density for the circular arc segment is: w′=w / g / t, where w is the given linear density of the pipe and t is the pipe wall thickness;

[0109] The arc length of the circular segment is: g = D × π / N, where D is the pipe diameter and N is the number of segments.

[0110] π = 3.1415926;

[0111] The corresponding length of the broken line segment is: g′=(D / 2×sin(2×π / N / 2))×2=D / sin(π / N);

[0112] According to the relationship between g and g′: fac=g / g′=D×π / N / (D / sin(π / N))=π / N / sin(π / N);

[0113] Shell element density: w″=w′×fac.

[0114] With this method of processing the shell element density, the calculated pipe weight will be correct regardless of how many segments the pipe is divided into circumferentially.

[0115] Therefore, the weight of the shell element component model obtained using this technique is completely consistent with the weight of the pipe beam, with no calculation discrepancy. This is crucial for dynamic analysis because the dynamic response of the problem (usually analyzed using the response spectrum method) is closely related to the mode shapes. Furthermore, the modes of the pipe problem are closely related to the mass distribution of the model.

[0116] In this embodiment, the nodes of the pipe beam elements at the connection between the target shell component mesh model and the pipe beam elements are designated as master nodes, and the nodes of the target shell component mesh model corresponding to the master nodes at the connection between the target shell component mesh model and the pipe beam elements are designated as slave nodes.

[0117] Finite element analysis was performed on the hybrid model to obtain the displacements of each node, including: at the connection between the target shell component mesh model and the pipe beam element, only the displacements of the main nodes were calculated.

[0118] The step of calculating the stress of each shell element based on the mesh node displacements of the target shell component mesh model specifically includes:

[0119] Based on the displacement of the master node, calculate the displacement of each slave node corresponding to the master node.

[0120] The displacements of each slave node, along with the displacements of other mesh nodes in the target shell component mesh model obtained from the finite element calculation, constitute the mesh node displacements of the target shell component mesh model.

[0121] The stress of each shell element is calculated based on the mesh node displacements of the target shell component mesh model.

[0122] When creating a pipe model, if a section of the pipe needs to be treated as a shell element component, then the connections to its two ends must be treated. It is assumed that the cross-section of the pipe at any point is always a plane, and this plane is rigid; this is a fundamental assumption in pipe calculations using beam elements. Therefore, at the end of a one-dimensional pipe, there is only one node (let's call it node n), and the component connected to it is changed to a shell element component. There are no nodes at this point, but there is a ring of nodes along the outer diameter of the pipe, and this ring of nodes is not independent; their displacements are entirely determined by node n. For example, Figure 3 This illustrates the connection between the pipe beam and shell elements. Nodes 8 and 9 form the pipe beam element, a one-dimensional line element. Nodes 21 to 26 represent a ring of nodes on the shell element boundary. The displacement solutions for these nodes are not included in the displacement unknowns of the structural equations in the finite element model; they are indirectly obtained from the displacement of node 9. The typical solution process usually ends here. However, this result is incomplete for temperature loads, lacking the effect of thermal expansion on rigid surfaces. The influence of thermal expansion can be considered when calculating the displacements of subordinate nodes, as each subordinate node is affected by thermal expansion, resulting in a change in its corresponding length R.

[0123] In this embodiment, before calculating the displacements of each slave node corresponding to the master node based on the displacement of the master node, the method further includes: determining whether the operating condition is a non-temperature operating condition or a temperature operating condition.

[0124] If the operating condition is determined to be a non-temperature operating condition, the displacement of each slave node corresponding to the master node is calculated using equation (2) based on the displacement of the master node:

[0125] d′=d×a (2)

[0126] Where d is the displacement of the master node, d′ is the displacement of the slave node corresponding to the master node, and a is the transformation matrix that converts the displacement of the master node to the displacement of the slave node.

[0127] If the operating condition is determined to be a temperature-related condition, the displacement of each slave node corresponding to the master node is calculated using equation (3) based on the displacement of the master node:

[0128] d′=d×(a×(1+alf)) (3)

[0129] Where alf is the coefficient of thermal expansion of the pipe material.

[0130] The aforementioned master node and its slave nodes form a rigid surface. Because this rigid surface does not deform, it is correct for general load solutions, but it causes problems for temperature loads. For the pipe beam model, the program only considers thermal expansion along the axial direction during calculation, and cannot calculate the circumferential thermal expansion of the pipe. However, for shell element components, after applying a temperature load, the shell element component can obtain both axial and circumferential thermal expansion displacements. At this time, unrealistic results will appear at the connection between the pipe beam element and the shell element component, due to this rigid surface. Therefore, it is necessary to consider the thermal displacement effect of each slave node. Without considering the temperature effect, the displacement of the auxiliary node is equal to the displacement of the master node transferred to the corresponding position: d′=d×a. When thermal expansion displacement needs to be considered: d′=d×(a×(1+alf)), where alf is the coefficient of thermal expansion of the material.

[0131] Current pipeline calculation and analysis software cannot directly combine pipeline elements and pipeline components described by shell elements for analysis and calculation. Pipeline calculations must be performed under various operating conditions, such as self-weight, temperature, and seismic conditions. Different operating conditions and operational levels require different evaluation standards, which are reflected in different standard formulas. The formulas used in pipeline evaluation employ many coefficients. The bending moment of the pipeline beam obtained from the pipeline calculation is directly input into the standard formulas; therefore, the actual stress is not directly obtained from the pipeline beam element. The limits required by the standard evaluation are allowable stresses. The program must consider various factors (such as welding, component type, number of loading cycles, etc.). The influence of these conditions is sometimes considered by coefficients given in the standard, such as the weld coefficient, which is related to the welding process and connecting components. Some conservative factors are unavoidable when using pipeline beams for calculations.

[0132] For equipment constructed from shell elements, the evaluation directly assesses stress. However, this stress can be categorized into membrane stress, bending stress, and membrane plus bending stress, which are related not only to the nature of the load but also to the evaluation location. The piping calculation program using the technology of this invention can conveniently complete the calculation of piping and equipment components in one step. The weight of the shell element component model obtained using this technology is completely consistent with the weight of the pipe beam, with no calculation discrepancy. This is crucial for dynamic analysis because the dynamic response of the problem (usually analyzed using the response spectrum method) is closely related to the mode shapes. The modes of the piping problem are closely related to the model's mass distribution. Another technical step is the connection between the pipe elements and shell elements, employing a master-slave node technique. The nodes at the pipe ends are master nodes, and the nodes on the shell model associated with these points are slave nodes. This technique ensures that these nodes, including the master and slave nodes on the plane, form a rigid plane that meets the calculation requirements of the entire problem. The shell element model established using this technique guarantees that the weight of the model is completely consistent with the mass of the pipe model. The requirements for pipeline evaluation are naturally met, and shell elements can directly provide element stresses, including membrane stress and bending stress. The software developed using these two technologies provides more realistic local results than conventional software and can complete the calculation and evaluation of pipeline and equipment components in one go. Because the program is very easy to use, work efficiency is greatly improved. At the same time, it eliminates many conservative elements in the design process, making pipeline design and construction more economical, thereby reducing the overall construction cost of the project.

[0133] The specific implementation of the method of this invention is reflected in the computer software flow. The following implementation process refers to the implementation process of any pipeline calculation program using the method of this invention. This does not include the technique of discretizing the side surface of the cylinder (i.e., the pipeline) into corresponding nodes and elements, nor does it include the solution algorithms for various elements in the finite element method, nor does it include the solution methods for master-slave nodes. These are all necessary functions of finite element method software, and many general-purpose software programs on the market have these functions. The implementation here refers to the technical operation steps required for pipeline calculation software to directly perform shell element calculations on some components in pipeline calculation problems.

[0134] 1) The first step is the standard pipe calculation. Based on the pipe problem to be calculated, a pipe beam model composed of multiple pipe beam elements needs to be generated. This step is standard in pipe calculation and is not relevant to this invention. However, it is a fundamental condition for the technology of this invention. We need to define the rules for dividing the shell elements, such as how many segments to divide circumferentially and axially, or simply specify the side lengths of the divided shell elements.

[0135] 2) When a beam element is required to be calculated as a shell component, the software needs to determine the original start and end node numbers, node coordinates, diameter, material, temperature, pressure, and other information of the beam element. The next step is to create a finite element solution model file, which must include all the information of the shell element, and the corresponding pipe beam element must be removed.

[0136] 3) For the start and end point coordinates of the second step, as well as the number of segments in the axial and circumferential directions, shell element mesh node coordinates and element number groups should be generated between the coordinates to describe the shell component. Each end of this shell component has a ring of nodes, which are subordinate nodes, belonging to the start and end point nodes of the original pipeline in the second step. The purpose of this is to ensure that the plane formed by the master and slave node groups can represent the pipeline cross-section as a rigid surface that will not deform.

[0137] 4) In standard pipe description files, the linear density of the pipe is defined when defining the pipe cross-section. The usual unit is mass per unit length, such as kilograms per meter. However, shell element calculations require the material density of the target shell component. During this model conversion, the principle to ensure is that the weight of the converted shell element component is consistent with the weight of the original input pipe element. The original pipe weight is W = pipe length * pipe linear weight. Theoretically, the total area of ​​the shell model of this pipe should equal the lateral surface area of ​​the cylinder of this pipe element. Therefore, the material density of the target shell component is q = W / shell element area / pipe wall thickness.

[0138] 5) Prepare the finite element file for pipeline calculation, start the finite element calculation for each calculation case, and the program solves the finite element equations.

[0139] 6) For problems with master and slave nodes, the displacement value of the slave node needs to be obtained from the displacement of the master node. This operation is only performed on results that are not for temperature conditions.

[0140] 7) For the displacement of subordinate nodes under temperature conditions, the influence of the thermal expansion coefficient at the corresponding temperature needs to be considered to calculate the displacement of subordinate nodes.

[0141] 8) Perform stress calculations for both the piping unit and the shell unit together, and conduct stress assessments for each unit separately according to the piping and equipment specifications.

[0142] Step 4) above yields the theoretical material density of the target shell component. However, in reality, since each shell element is a plane, it differs from the curved surface of the cylindrical pipe. Therefore, the theoretical density for the pipe surface can be calculated as: w′=w / (D×π) / t. Considering the shell element's plane-to-surface relationship, w″=w′×fac, where fac=π / N / π(π / N). The coefficient fac is used because when manufacturing the shell component, the pipe density needs to be amplified due to the reduced surface area.

[0143] In step 7), when calculating the displacement of the subordinate node, the influence of the thermal expansion coefficient must be considered. d′=d×(a×(1+alf)), where d is the calculated displacement of the master node, a is the transformation matrix for converting the master node displacement to the subordinate node displacement, and alf is the thermal expansion coefficient of the material.

[0144] Example 2:

[0145] like Figure 4 As shown, this embodiment provides a pipe mechanics calculation device for implementing the method of Embodiment 1, comprising:

[0146] Pipe beam generation module 1 is used to generate a pipe beam model composed of multiple pipe beam elements connected together, as well as the node information of each pipe beam element, based on the parameter information of each component in the pipe to be calculated. Each component corresponds one-to-one with a pipe beam element.

[0147] Shell generation module 2 is used to acquire the start and end node information and mesh generation information of the target shell component that needs to be analyzed in detail, generate a target shell component mesh model formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model.

[0148] Replacement module 3 is used to replace the pipe beam elements at corresponding positions in the pipe beam model with the target shell component mesh model to form a hybrid model.

[0149] Finite element calculation module 4 is used to perform finite element calculations on the hybrid model based on the operating condition information of the pipeline to be calculated and the parameter information of each component, to obtain the displacement of each node of the hybrid model, to calculate the nodal internal forces of the pipeline beam elements based on the nodal displacements of the pipeline beam elements, and to calculate the stress of each shell element based on the mesh nodal displacements of the target shell component mesh model.

[0150] Stress calculation module 5 calculates the stress of the pipe beam element based on the nodal internal forces of the pipe beam element.

[0151] In this embodiment, an interface module 7 is also included, which is used to receive the operating condition information of the pipeline to be calculated and the parameter information of each component, and transmit them to the pipeline beam generation module 1 and the finite element calculation module 4.

[0152] It is also used to receive the target shell component's numbering information and mesh division information and transmit them to the shell generation module 2.

[0153] In this embodiment, a shell parameter forming module 6 is also included, which is electrically connected to the interface module 7. It is used to determine the material density of the target shell component based on the linear density of the target shell component, and replace the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component.

[0154] In this embodiment, the shell parameter forming module 6 includes a material density calculation module 61 and a shell parameter updating module 62. The material density calculation module 61 is electrically connected to the interface module 7 and is used to determine the material density of the target shell component based on the linear density of the target shell component. The shell parameter updating module 62 is electrically connected to both the interface module 7 and the material density calculation module 61 and is used to replace the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component.

[0155] The material density calculation module 61 determines the material density of the target shell component based on its linear density, specifically including:

[0156] Based on the linear density w of the target shell component, its original material density w′ is determined using the formula: w′=w / g / t, where, after the target shell component is circumferentially segmented, the end face circle forms N arcs, g is the length of the arc, g=πD / N, t is the wall thickness of the target shell component, and D is the pipe diameter of the target shell component.

[0157] Based on the number of circumferential segments of the target shell component, its circumferential reduced density coefficient fac is calculated. The calculation formula is: fac=g / g′, where g′ is the length of the broken line segment corresponding to the arc after circumferential segmentation of the target shell component, g′=2D×sin(180 / N).

[0158] Then calculate the material density w″ of the target shell component according to the following formula:

[0159] w″=w′×fac.

[0160] In this embodiment, the nodes of the pipe beam elements at the connection between the target shell component mesh model and the pipe beam elements are designated as master nodes, and the nodes of the target shell component mesh model corresponding to the master nodes at the connection between the target shell component mesh model and the pipe beam elements are designated as slave nodes.

[0161] The finite element calculation module 4 includes a total nodal displacement calculation module 41, a mesh nodal displacement formation module 42, a beam element internal force calculation module 44, and a shell element stress calculation module 43.

[0162] The total node displacement calculation module 41 is used to perform finite element calculations on the hybrid model to obtain the displacements of each node in the hybrid model. This includes calculating the displacements of only the main nodes at the connection points between the target shell component mesh model and the pipe beam elements.

[0163] The mesh node displacement forming module 42 is electrically connected to the total node displacement calculation module 41. It is used to calculate the displacements of each slave node corresponding to the master node based on the displacement of the master node. It is also used to summarize the displacements of each slave node, along with the other mesh node displacements of the target shell component mesh model obtained from the finite element calculation, to form the mesh node displacements of the target shell component mesh model.

[0164] The beam element internal force calculation module 44 is electrically connected to the total nodal displacement calculation module 41, and is used to calculate the nodal internal forces of the pipe beam element based on the nodal displacements of the pipe beam element.

[0165] The shell element stress calculation module 43 is electrically connected to the mesh node displacement forming module 42, and is used to calculate the stress of each shell element based on the mesh node displacement of the target shell component mesh model.

[0166] The mesh node displacement forming module 42 includes a shell slave node displacement calculation module 421 and a shell node displacement summarizing module 422. The shell slave node displacement calculation module 421 is electrically connected to the total node displacement calculation module 41 and is used to calculate the displacement of each slave node corresponding to the master node based on the displacement of the master node. The shell node displacement summarizing module 422 is electrically connected to both the shell slave node displacement calculation module 421 and the total node displacement calculation module 41 and is used to summarize the displacements of each slave node and the other mesh node displacements of the target shell component mesh model obtained in the finite element calculation to form the mesh node displacement of the target shell component mesh model.

[0167] In this embodiment, the finite element calculation module 4 further includes a judgment module 45, which is electrically connected between the interface module 7 and the shell slave node displacement calculation module 421, and is used to determine whether the operating condition is a non-temperature operating condition or a temperature operating condition.

[0168] If the operating condition is determined to be a non-temperature-related condition, the shell slave node displacement calculation module 421 is triggered to calculate the displacement of each slave node corresponding to the master node using the following formula based on the displacement of the master node:

[0169] d′=d×a

[0170] Where d is the displacement of the master node, d′ is the displacement of the slave node corresponding to the master node, and a is the transformation matrix that converts the displacement of the master node to the displacement of the slave node.

[0171] If the operating condition is determined to be a temperature-related condition, the shell slave node displacement calculation module 421 is triggered to calculate the displacement of each slave node corresponding to the master node using the following formula based on the displacement of the master node:

[0172] d′=d×(a×(1+alf))

[0173] Where alf is the coefficient of thermal expansion of the pipe material.

[0174] Application Cases

[0175] For a practical engineering piping problem, if the original piping is as follows: Figure 5 As shown, many software programs can currently perform this type of calculation. The internal torque M in the pipe is calculated, and then the result is substituted into the standard formula for evaluation. The evaluation requirements are as follows: Figure 6 As shown. Figure 6 In the equation, D and Z are the pipe diameter and bending modulus given in the problem. S on the left side of the equal sign is the calculated stress, and S on the right side of the less than or equal to sign is the allowable stress of the material given in the standard.

[0176] The program corresponding to the method of this invention (i.e., Example 2) can automatically build a model of a shelled unit, such as... Figure 7 As shown. Such problems have corresponding calculation results, and their deformation under self-weight conditions is as follows. Figure 8 As shown. The evaluation of the calculated stress of the shell is divided into overall membrane, local membrane, and bending stress according to the specification, and is carried out according to the evaluation requirements as follows. Figure 9 As shown.

[0177] As can be seen, this invention allows for the simultaneous calculation of pipe beam and shell unit components, including stress assessment, without any unnecessary conservative combination processing. The advantages are obvious: the program can obtain results for pipe and shell unit components in a single operation, regardless of temperature, seismic conditions, or other factors. This increases the accuracy of analysis and calculation, reduces the conservatism in design, and ultimately improves the economy and safety of engineering projects.

[0178] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for calculating pipeline mechanics, characterized in that, include: Based on the parameter information of each component in the pipeline to be calculated, a pipeline beam model composed of multiple pipeline beam elements is generated, along with the node information of each pipeline beam element. There is a one-to-one correspondence between components and pipeline beam elements. Obtain the start and end node information and mesh generation information of the target shell component that needs detailed analysis, generate a target shell component mesh model formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model. The target shell component mesh model is used to replace the corresponding pipe beam elements in the pipe beam model to form a hybrid model. Based on the operating conditions of the pipeline and the parameter information of each component, finite element analysis is performed on the hybrid model to obtain the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the nodal internal forces of the pipeline beam elements are calculated. Based on the mesh node displacements of the target shell component mesh model, the stresses of each shell element are calculated. Calculate the stress of the pipe beam element based on the nodal internal forces of the pipe beam element; The method further includes: determining the material density of the target shell component based on the linear density of the target shell component, and replacing the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component; The determination of the material density of the target shell component based on its linear density specifically includes: Based on the linear density w of the target shell component, its original material density w′ is determined using the formula: w′=w / g / t, where after the target shell component is circumferentially segmented, the end face circle forms N arcs, g is the length of the arc, g=πD / N, t is the wall thickness of the target shell component, and D is the pipe diameter of the target shell component. Based on the number of circumferential segments of the target shell component, calculate its circumferential reduced density coefficient fac. The calculation formula is: fac=g / g′, where g′ is the length of the broken line segment corresponding to the arc after circumferential segmentation of the target shell component, g′=2 D×sin(180 / N). Then calculate the material density w″ of the target shell component according to the following formula: w″ = w′ × fac.

2. The pipe mechanics calculation method according to claim 1, characterized in that, let... The nodes of the pipe beam elements at the connection between the target shell component mesh model and the pipe beam elements are designated as master nodes, and the nodes of the target shell component mesh model corresponding to the master nodes at the connection between the target shell component mesh model and the pipe beam elements are designated as slave nodes. Finite element analysis was performed on the hybrid model to obtain the displacements of each node, including: at the connection between the target shell component mesh model and the pipe beam element, only the displacements of the main nodes were calculated. The step of calculating the stress of each shell element based on the mesh node displacements of the target shell component mesh model specifically includes: Based on the displacement of the master node, calculate the displacement of each slave node corresponding to the master node. The displacements of each slave node, along with the displacements of other mesh nodes in the target shell component mesh model obtained from the finite element calculation, constitute the mesh node displacements of the target shell component mesh model. The stress of each shell element is calculated based on the mesh node displacements of the target shell component mesh model.

3. The pipe mechanics calculation method according to claim 2, characterized in that, Before calculating the displacements of each slave node corresponding to the master node based on the displacement of the master node, the process further includes: determining whether the operating condition is a non-temperature operating condition or a temperature operating condition. If the operating condition is determined to be a non-temperature operating condition, the displacement of each slave node corresponding to the master node is calculated using equation (2) based on the displacement of the master node: d′=d×a (2) Where d is the displacement of the master node, d′ is the displacement of the slave node corresponding to the master node, and a is the transformation matrix that converts the displacement of the master node to the displacement of the slave node. If the operating condition is determined to be a temperature-related condition, the displacement of each slave node corresponding to the master node is calculated using equation (3) based on the displacement of the master node: d′=d×(a×(1+alf)) (3) Where alf is the coefficient of thermal expansion of the pipe material.

4. A pipe mechanics calculation device, characterized in that, include: The pipe beam generation module is used to generate a pipe beam model composed of multiple pipe beam elements connected together, based on the parameter information of each component in the pipe to be calculated, as well as the node information of each pipe beam element. There is a one-to-one correspondence between components and pipe beam elements. The shell generation module is used to obtain the start and end node information and mesh generation information of the target shell component that needs to be analyzed in detail, generate a mesh model of the target shell component formed by splicing multiple shell elements, and the mesh node information of the target shell component mesh model. The replacement module is used to replace the pipe beam elements at corresponding positions in the pipe beam model with the target shell component mesh model to form a hybrid model. The finite element method (FEM) module is used to perform FEM calculations on the hybrid model based on the operating conditions of the pipeline and the parameter information of each component. This yields the displacements of each node in the hybrid model. Based on the node displacements of the pipeline beam elements, the module calculates the nodal internal forces of the pipeline beam elements. Based on the mesh node displacements of the target shell component mesh model, the module calculates the stresses of each shell element. The stress calculation module calculates the stress of the pipe beam element based on the nodal internal forces of the pipe beam element. The device further includes a shell parameter forming module, which is electrically connected to the interface module. It is used to determine the material density of the target shell component based on the linear density of the target shell component, and replace the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information of the target shell component. The shell parameter formation module includes a material density calculation module and a shell parameter update module. The material density calculation module is electrically connected to the interface module and is used to determine the material density of the target shell component based on its linear density. The shell parameter update module is electrically connected to the material density calculation module and is used to replace the linear density in the parameter information of the target shell component with the material density of the target shell component to form updated parameter information for the target shell component. The material density calculation module determines the material density of the target shell component based on its linear density, specifically including: Based on the linear density w of the target shell component, its original material density w′ is determined using the formula: w′=w / g / t, where after the target shell component is circumferentially segmented, the end face circle forms N arcs, g is the length of the arc, g=πD / N, t is the wall thickness of the target shell component, and D is the pipe diameter of the target shell component. Based on the number of circumferential segments of the target shell component, calculate its circumferential reduced density coefficient fac. The calculation formula is: fac=g / g′, where g′ is the length of the broken line segment corresponding to the arc after circumferential segmentation of the target shell component, g′=2 D×sin(180 / N). Then calculate the material density w″ of the target shell component according to the following formula: w″ = w′ × fac.

5. The pipeline mechanics calculation device according to claim 4, characterized in that, It also includes an interface module, which receives the operating condition information of the pipeline to be calculated and the parameter information of each component, and transmits them to the pipeline beam generation module and the finite element calculation module. It is also used to receive the target shell component's numbering information and mesh generation information and transmit them to the shell generation module.

6. The pipe mechanics calculation device according to any one of claims 4-5, characterized in that, Let the nodes of the pipe beam elements at the connection between the target shell component mesh model and the pipe beam elements be the master nodes, and let the nodes of the target shell component mesh model corresponding to the master nodes at the connection between the target shell component mesh model and the pipe beam elements be the slave nodes. The finite element calculation module includes a total nodal displacement calculation module, a mesh nodal displacement generation module, a beam element internal force calculation module, and a shell element stress calculation module. The total node displacement calculation module is used to perform finite element calculations on the hybrid model to obtain the displacements of each node in the hybrid model. This includes calculating the displacements of only the main nodes at the connection points between the target shell component mesh model and the pipe beam elements. The mesh node displacement forming module is electrically connected to the total node displacement calculation module. It is used to calculate the displacements of each slave node corresponding to the master node based on the master node's displacement. It is also used to summarize the displacements of each slave node, along with the other mesh node displacements of the target shell component mesh model obtained from the finite element calculation, to constitute the mesh node displacements of the target shell component mesh model. The beam element internal force calculation module is electrically connected to the total nodal displacement calculation module, and is used to calculate the nodal internal forces of the pipe beam element based on the nodal displacements of the pipe beam element. The shell element stress calculation module is electrically connected to the mesh node displacement forming module and is used to calculate the stress of each shell element based on the mesh node displacement of the target shell component mesh model.

7. The pipeline mechanics calculation device according to claim 6, characterized in that, The finite element calculation module also includes a judgment module, which is electrically connected between the interface module and the mesh node displacement forming module, and is used to determine whether the working condition is a non-temperature condition or a temperature condition. If the operating condition is determined to be a non-temperature operating condition, the mesh node displacement generation module is triggered to calculate the displacement of each slave node corresponding to the master node using equation (2) based on the displacement of the master node: d′=d×a (2) Where d is the displacement of the master node, d′ is the displacement of the slave node corresponding to the master node, and a is the transformation matrix that converts the displacement of the master node to the displacement of the slave node. If the operating condition is determined to be a temperature-related condition, the mesh node displacement generation module is triggered to calculate the displacement of each slave node corresponding to the master node using equation (3) based on the displacement of the master node: d′=d×(a×(1+alf)) Where alf is the coefficient of thermal expansion of the pipe material.

8. The pipeline mechanics calculation device according to claim 6, characterized in that, The mesh node displacement generation module includes a shell node displacement calculation module and a shell node displacement aggregation module. The shell slave node displacement calculation module is electrically connected to the master node displacement calculation module, and is used to calculate the displacement of each slave node corresponding to the master node based on the displacement of the master node. The shell node displacement summarization module is electrically connected to the shell slave node displacement calculation module and the total node displacement calculation module, respectively. It is used to summarize the displacements of each slave node and the other mesh node displacements of the target shell component mesh model obtained in the finite element calculation to form the mesh node displacements of the target shell component mesh model.

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