A method for analyzing the seismic response of a nuclear island plant building considering the coupling effect of a complex support type of a pressure water tank

Abstract

This invention relates to the field of nuclear power plant design, and more particularly to a method for analyzing the seismic response of a nuclear island building considering the coupling effect of a pressurized water tank with complex support structures. The method involves: using the finite element software ANSYS to create separate finite element models of the nuclear island building structure and the pressurized water tank, and then merging these two models into a single model; processing the connection area between the merged model and the pressurized water tank to form a coupling model of the pressurized water tank and the nuclear island building; using ANSYS, through macro commands, obtaining the stiffness matrix, damping matrix, and mass matrix of the entire system considering the coupling effect of the pressurized water tank and the nuclear island building; using ACS SASSI analysis software to retrieve the extracted three matrices of the entire system, forming an analysis model of the superstructure considering the coupling effect of the pressurized water tank and the nuclear island building; and based on this analysis model, supplementing soil parameters, seismic input, and the interaction points between the two to perform seismic response analysis of the nuclear island building. This invention is suitable for joint analysis of complex situations, and the calculation results are accurate.

Description

Technical Field

[0001] This invention relates to the field of nuclear building design, and in particular to a method for analyzing the seismic response of nuclear island buildings that takes into account the coupling effect of pressurized water tanks with complex support structures. Background Technology

[0002] For equipment in nuclear island buildings, to facilitate engineering design, the common practice is to simulate the equipment as a mass point added to the building structure to account for its impact. This simplified calculation method can meet the requirements for calculation and analysis of equipment with small mass and simple connection between the equipment and the building structure. However, for large equipment with complex support structures, this simplified method ignores the interaction between the equipment and the structure in the seismic response at the support location, leading to inaccurate calculation results.

[0003] Nuclear power plant buildings contain a variety of large pieces of equipment. These large pieces of equipment are heavy and have complex support structures. Under earthquake action, they inevitably have a significant impact on the dynamic characteristics of the building structure, especially on the local dynamic response at the support locations.

[0004] Taking the two spherical shell external pressure tanks in subsequent Hualong reactor models as examples, the tanks have a diameter of 18m and a total mass of approximately 3500t (tank mass + water mass). Located on the floor slab at an elevation of 20m above the nuclear auxiliary plant and backup cooling plant, the design must consider not only seismic forces but also internal pressure and thermal expansion. Under seismic conditions, the support constraints need to be sufficiently strong to ensure high overall structural rigidity; while under thermal expansion conditions, the constraints on the support locations need to be released as much as possible to ensure that the large pressure tanks can expand freely without transferring force to the plant structure.

[0005] Due to the highly complex support structure between the elevated, ultra-large pressurized water tank and the plant structure, and the fact that the pressurized water tank weighs 3500 tons, the seismic response is extremely large, and the local effects of the interaction between the elevated, ultra-large pressurized water tank and the plant structure cannot be ignored. For this type of elevated, ultra-large pressurized water tank, using a simplified mass point approach cannot guarantee the accuracy of the calculation results. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a seismic response analysis method for nuclear island buildings that takes into account the coupling effect of pressurized water tanks with complex support structures. This method is suitable for joint analysis in complex situations, provides accurate calculation results, and meets the needs of seismic response analysis for large equipment with complex support structures coupled with the building structure in nuclear power plants.

[0007] This invention provides a seismic response analysis method for nuclear island buildings considering the coupling effect of pressurized water tanks with complex support structures, characterized by comprising:

[0008] Step 1: Use the finite element software ANSYS to complete the finite element model of the nuclear island plant structure and the pressurized water tank respectively, and then combine the two models into one model;

[0009] Step 2: Process the connection area between the splicing model and the pressurized water tank to form a coupled model of the pressurized water tank and the nuclear island building;

[0010] Step 3: Using the finite element software ANSYS, the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building are obtained through the macro commands compiled.

[0011] Step 4: The earthquake ACS SASSI analysis software calls up the extracted stiffness matrix [K], damping matrix [C] and mass matrix [M] of the entire system to form an analysis model of the superstructure of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building;

[0012] Step 5: Based on the analysis model, add soil layer parameters, seismic input, and the interaction points between the two to conduct seismic response analysis of the nuclear island plant.

[0013] In a specific embodiment of the present invention, in step 1, the finite element model of the pressurized water tank is simplified.

[0014] In one specific embodiment of the present invention, the finite element model of the pressurized water tank includes a main body of the pressurized water tank, and multiple supports are connected to the middle position of the pressurized water tank and are evenly distributed along the circumference of the pressurized water tank. Each support is provided with bolt holes for anchor bolts to pass through. A ring wall groove is opened on the ring wall, and the support is set in the ring wall groove. Anchor bolts embedded in the bottom surface of the ring wall groove pass through the bolt holes on the support. An upper tie rod bracket and a lower tie rod bracket are also provided on the ring wall. The upper tie rod is connected to the upper part of the pressurized water tank, and the other end of the upper tie rod is hinged to the upper tie rod bracket. One end of the lower tie rod is connected to the lower part of the pressurized water tank, and the other end of the lower tie rod is hinged to the lower tie rod bracket.

[0015] In a specific embodiment of the present invention, the simplified processing method is as follows: only the main structure of the pressurized water tank is considered; and a simple support structure is used to replace the internal support structure and its connection of the pressurized water tank, so as to ensure that the mass and rigidity of the pressurized water tank remain unchanged.

[0016] The nonlinear contact problem between the lug and the wall pier, characterized by only compression and no tension, is simplified.

[0017] In a specific embodiment of the present invention, step 2 specifically includes:

[0018] The surface-to-surface connection of the finite element model of the nuclear island plant structure and the finite element model of the pressurized water tank is transformed into a point-to-point connection. By changing the local area of ​​the nuclear island plant supporting the pressurized water tank into a solid element model, a mesh design is formed to realize the mutual transfer of load between the pressurized water tank and the plant structure, thereby forming a local coupling model of the pressurized water tank and the plant structure.

[0019] In a specific embodiment of the present invention, the method for converting surface-to-surface connections into point-to-point connections is as follows: A coupled connection between surfaces and points is established using multi-point constraint equations, and then a coupled connection between points is established using constraint equilibrium equations, thereby achieving the conversion of the connection method, as shown in the following equation:

[0020] Multi-point constraint equations:

[0021]

[0022] Among them U i Let U be the degree of freedom of node i (the node at the point). j n is the degree of freedom of the master node j (nodes on the surface), and n is the number of coupled nodes on the surface;

[0023] C j The weighting coefficient for the coupling connection of the master node is a function of the distance between the master node and the slave node and the load distribution of different nodes, and the value range is (-1, 1).

[0024] Among them U i Let U be the degree of freedom of node i (the node at the point). j n is the degree of freedom of the master node j (nodes on the surface), and n is the number of coupled nodes on the surface;

[0025] C j The weighting coefficient for the coupling connection of the master node is a function of the distance between the master node and the slave node and the load distribution of different nodes, and the value range is (-1, 1).

[0026] CD is a constant and must satisfy the force and displacement equilibrium equations of the master node and slave node.

[0027] In a specific embodiment of the present invention, the extraction method is mainly based on the element motion equations in the finite element method as follows:

[0028]

[0029] The stiffness matrix is: [K]=∫ V [B] T [D][B]dv; The mass matrix is: [M]=∫ V [B] T ρ[N]dv; The damping matrix is: [C]=∫ V [B]T γ[N]dv; The equivalent nodal load caused by the volume force acting on the element is: [F]; The elastic force acting on the element is: [K]{q}; The damping force acting on the element is: The inertial force acting on the element is:

[0030] In a specific embodiment of the present invention, step 3 specifically includes:

[0031] In ANSYS software, the stiffness matrix [K] of the building structure is extracted using macro commands. 11 [ ], damping matrix [C1] and mass matrix [M1], stiffness matrix of the connecting region [K 22 [ ], damping matrix [C2] and mass matrix [M2], and pressure tank stiffness matrix [K 33 [ ], damping matrix [C3] and mass matrix [M3], local stiffness [K] between the plant structure and the connecting area 12 ] and [K 21 ] and the local stiffness [K] between the pressurized water tank and the connecting area 23 ] and [K 32 By integrating the above stiffness matrix, damping matrix, and mass matrix, we obtain the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building. The matrices of the entire system are as follows:

[0032]

[0033] Where q1 represents the displacement of the plant structure unit, q2 represents the displacement of the connecting area unit, and q3 represents the displacement of the pressurized water tank unit. This indicates the speed on the structural unit of the factory building. Indicates the velocity on the connected region unit. This indicates the speed on the pressurized water tank unit. This represents the acceleration on the structural unit of the factory building. This represents the acceleration on the connected region element. This indicates the acceleration on the pressurized water tank unit.

[0034] F1 represents the equivalent nodal load caused by the volume force acting on the structural unit of the factory building;

[0035] F2 represents the equivalent nodal load caused by the volume force acting on the connected region element;

[0036] F3 represents the equivalent nodal load caused by the volume force acting on the pressurized water tank unit.

[0037] In a specific embodiment of the present invention, in step 3, the finite element software ANSYS extracts the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system and generates a COO file suitable for earthquake ACS SASSI analysis software.

[0038] In a specific embodiment of the present invention, in step 4, the COO files of the stiffness matrix [K], damping matrix [C] and mass matrix [M] of the entire system are called, and the HOUSEFSA module in the ACS SASSI analysis software is used to form an analysis model of the superstructure of the entire system that considers the coupling effect between the pressurized water tank and the nuclear island building.

[0039] In a specific embodiment of the present invention, the ACS SASSI analysis software uses the spatial substructure method to handle related issues of SSI analysis. The superstructure is a finite element model, the foundation soil layer is assumed to be horizontally infinitely layered, the viscoelastic soil layer lies beneath a uniform elastic half-space, and the complex frequency response analysis method is used for seismic response analysis.

[0040] Compared with the prior art, the seismic response analysis method of the nuclear island plant considering the coupling effect of pressurized water tanks with complex support structures, as proposed in this invention, has the following beneficial effects:

[0041] (1) Taking into account the interaction between the high-level ultra-large pressurized water tank and the plant structure coupling area, as well as the interaction between the soil and the structure, a comprehensive seismic response analysis was conducted, which improved the accuracy of the analysis.

[0042] (2) By extracting the local mass matrix, stiffness matrix and damping matrix of the connection area, the interaction between the complex-supported pressurized water tank and the plant structure coupling area is considered, which improves the calculation efficiency and facilitates engineering application.

[0043] (3) It is conducive to a comprehensive analysis of the response mechanisms of equipment and structural systems under various working conditions, ensuring the rigor of the design process and design logic, and making the design results as close as possible to the actual engineering situation. It solves the problem of conservative design calculations for ultra-large equipment and structures, and maximizes the economic efficiency of the project. Attached Figure Description

[0044] Figure 1 A schematic diagram illustrating the complex support structure of a high-level, ultra-large pressurized water tank held in place by a ring wall.

[0045] Figure 2 This describes the ring wall clamping scheme for the nuclear island plant.

[0046] Figure 3 The unsimplified force diagram shows the nonlinear contact between the lug and the wall pier, where there is only compression and no tension.

[0047] Figure 4Force diagram for a simplified treatment of nonlinear contact between the lug and the wall pier where there is only compression and no tension;

[0048] Figure 5 This is a flowchart of the calculation steps for seismic response analysis considering the coupling effect between the high-level ultra-large pressurized water tank and the nuclear island building in this invention.

[0049] Figure 6 This is the finite element model of the nuclear island plant built using the general-purpose software ANSYS in this invention;

[0050] Figure 7 This is the finite element model of the pressurized water tank established by the general-purpose software ANSYS in this invention;

[0051] Figure 8 This is the coupling model of the pressurized water tank and the nuclear island building established by the general-purpose software ANSYS in this invention;

[0052] In the diagram, 1-pressurized water tank, 2-structural support system, 21-support ring wall, 22-basic structure of the factory building, 23-reinforcing plate, 221-floor slab, 222-side wall, 211-ring wall groove, 212-upper support pier, 213-lower support pier;

[0053] 3-Support, 4-Upper tie rod, 5-Lower tie rod, 6-Bolt hole, 7-Anchor bolt. Detailed Implementation

[0054] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0055] This invention analyzes the seismic response of the pressurized water tank and the plant structure, focusing on the coupling effect. The relationship between the pressurized water tank and the ring wall of the nuclear island plant is as follows: Figures 1-2 As shown.

[0056] Includes: a pressurized water tank 1 and a structural support system 2;

[0057] Structural support system 2 includes: basic factory structure 22, supporting ring wall 21, and reinforcing plate 23;

[0058] The pressurized water tank 1 includes a support 3, an upper pull rod 4, a lower pull rod 5, anchor bolts 7, and bolt holes 6. The support 3 is connected to the middle position of the pressurized water tank 1 by welding. There are multiple supports 12, which are evenly distributed along the circumference of the pressurized water tank 1. Each support 3 includes a welding surface, two side surfaces, a bottom surface, and a top surface. In the embodiment of the present invention, the number of supports 3 is selected to be 20. The top and bottom surfaces of the support 3 are provided with multiple through bolt holes for the anchor bolts 7 to pass through. The bolt holes are of an elongated oval structure, which allows the support 3 to slide radially as a whole and ensures that the anchor bolts 8 only bear vertical tensile force under various operating conditions. The anchor bolts 7 can bear vertical upward throwing force and do not bear any lateral load. The support side surface, support side surface, and support bottom surface of the support 3 are smooth planes. The welding surface of the support 3 is fixed to the middle position of the pressurized water tank 1 by welding.

[0059] The basic structure 22 of the factory building includes floor slabs 221, side walls 222, and their associated supporting wall structures. A reinforcing plate 23 is provided between the side walls 222 and the supporting ring wall 21 of the basic structure of the factory building to improve the overall load-bearing capacity of the structural support system 2.

[0060] The supporting ring wall 21 is a ring-shaped reinforced concrete structure, and its bottom is integrated with the floor slab 221.

[0061] The supporting ring wall 21 has ring wall grooves 211, and the protruding part of the ring wall forms a ring wall pier. The ring wall grooves 211 and the ring wall piers are alternately arranged on the ring wall. The support 3 is located in the ring wall grooves 211. The number and distribution of the ring wall grooves 211 are the same as those of the support 3.

[0062] The two sides and bottom of the groove 211 of the ring wall are in contact with the two sides and bottom of the support 3. The two sides are used to bear the horizontal load under various operating conditions, and the bottom is used to bear the vertical downward load such as self-weight and earthquake. The anchor bolts 8 embedded in the bottom of the groove of the ring wall pass through the elongated bolt holes on the support 3. Under the earthquake condition, the upward load can be borne by the anchor bolts 7. Under the thermal expansion condition, the support 3 can slide radially in the groove of the ring wall to avoid thermal expansion load on the support.

[0063] The upper end of the supporting ring wall 21 is provided with an upper support pier 212 for installing and connecting the upper tie rod 5, and the lower end is provided with a lower support pier 213 for installing and connecting the lower tie rod 5.

[0064] One end of the upper pull rod 4 is connected to the upper part of the pressurized water tank 1 by a hinge. The upper pull rod 4 is used to enhance the overall rigidity of the pressurized water tank 1 and improve the seismic resistance of the pressurized water tank 1. The other end of the upper pull rod 4 is hinged to the upper pull rod bracket 9 to ensure that the upper pull rod 4 is a two-force rod.

[0065] One end of the pull rod 5 is connected to the lower part of the pressurized water tank 1 by a hinge. The pull rod 5 is used to enhance the overall rigidity of the pressurized water tank 1 and improve the seismic resistance of the pressurized water tank 1. One end of the pull rod 5 is hinged to the pull rod bracket 10 to ensure that the pull rod 5 is a two-force member.

[0066] Multiple upper pull rods 4 and lower pull rods 5 are provided and arranged around the perimeter of the high-level ultra-large pressurized water tank 1. In the embodiment of the present invention, there are 8 upper pull rods 4 and 20 lower pull rods 5.

[0067] The reinforcing plates 23 are used to strengthen the connection between the basic structure of the factory building and the ring wall, thereby improving the load-bearing capacity of the structural support system. In an embodiment of the present invention, the reinforcing plates 23 are distributed at the four corners of the basic structure of the factory building 22, with two reinforcing plates distributed above and below each corner, for strengthening the connection between the basic structure of the factory building 22 and the supporting ring wall 21, thereby improving the overall load-bearing capacity of the structural support system 2.

[0068] Embodiments of the present invention disclose a seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, such as... Figure 5 As shown, it includes:

[0069] Step 1: Use the finite element software ANSYS to complete the finite element models of the nuclear island building structure and the pressurized water tank, respectively. Figure 6 and Figure 7 As shown, the two models are combined into one model;

[0070] The finite element model of the pressurized water tank includes the pressurized water tank, with multiple supports connected in the middle of the pressurized water tank and evenly distributed along the circumference of the pressurized water tank. Each support is provided with bolt holes for anchor bolts to pass through. A ring wall groove is opened in the ring wall groove, and the support is set in the ring wall groove. Anchor bolts embedded in the bottom surface of the ring wall groove pass through the bolt holes on the support. An upper tie rod bracket and a lower tie rod bracket are also provided on the ring wall. The upper tie rod is connected to the upper part of the pressurized water tank, and the other end of the upper tie rod is hinged to the upper tie rod bracket. One end of the lower tie rod is connected to the lower part of the pressurized water tank, and the other end of the lower tie rod is hinged to the lower tie rod bracket.

[0071] Considering that this calculation is only to obtain a more accurate seismic response of the nuclear island plant, the finite element model of the pressurized water tank is simplified while ensuring that the mass and stiffness of the pressurized water tank remain unchanged.

[0072] The simplified approach is as follows: only the main structure of the pressurized water tank is considered; and a simple support structure is used to replace the internal support structure and its connections of the pressurized water tank, thereby reducing the influence of local modes.

[0073] The nonlinear contact problem between the supports and the wall piers, characterized by compression but no tension, is simplified. Considering that both the building structure and the pressurized water tank are designed for seismic resistance in the nuclear island plant, the nonlinear contact problem between the supports and the wall piers is simplified to one side being bound while the other side is not in contact. Although there are local differences in stress, the impact on the overall seismic response of the nuclear island plant is relatively small. Details of the simplification method are provided in the appendix. Figure 4 .

[0074] Step 2: Process the connection area between the spliced ​​model and the pressurized water tank to form a coupled model of the pressurized water tank and the nuclear island building, such as... Figure 8 As shown;

[0075] The surface-to-surface connections of the finite element models of the nuclear island plant structure and the pressurized water tank are transformed into point-to-point connections. By converting the local area of ​​the nuclear island plant supporting the pressurized water tank into a solid element model, a mesh design is formed to realize the mutual transfer of loads between the pressurized water tank and the plant structure, thereby forming a local coupling model of the pressurized water tank and the plant structure.

[0076] The method for transforming surface-to-surface connections into point-to-point connections is as follows: Multi-point constraint equations are used to establish coupled connections between surfaces and points, and then constraint equilibrium equations are used to establish coupled connections between points, thus achieving the transformation of the connection method, as shown in the following equation:

[0077] Multi-point constraint equations:

[0078]

[0079] Among them U i Let U be the degree of freedom of node i (the node at the point). j n is the degree of freedom of the master node j (nodes on the surface), and n is the number of coupled nodes on the surface;

[0080] C j The weighting coefficient for the coupling connection of the master node is a function of the distance between the master node and the slave node and the load distribution of different nodes, and the value range is (-1, 1).

[0081] Among them U i Let U be the degree of freedom of node i (the node at the point). j n is the degree of freedom of the master node j (nodes on the surface), and n is the number of coupled nodes on the surface;

[0082] C j The weighting coefficient for the coupling connection of the master node is a function of the distance between the master node and the slave node and the load distribution of different nodes, and the value range is (-1, 1).

[0083] CD is a constant and must satisfy the force and displacement equilibrium equations of the master node and slave node.

[0084] Through the processing of the above-mentioned connection area, the final coupling model of the pressurized water tank and the nuclear island plant is obtained.

[0085] Step 3: Using the finite element software ANSYS, the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building are obtained through the macro commands compiled.

[0086] Specifically, the steps include the following:

[0087] In ANSYS software, the stiffness matrix [K] of the building structure is extracted using macro commands. 11 [ ], damping matrix [C1] and mass matrix [M1], stiffness matrix of the connecting region [K 22 [ ], damping matrix [C2] and mass matrix [M2], and pressure tank stiffness matrix [K 33 [ ], damping matrix [C3] and mass matrix [M3], local stiffness [K] between the plant structure and the connecting area 12 ] and [K 21 ] and the local stiffness [K] between the pressurized water tank and the connecting area 23 ] and [K 32 ];

[0088] The extraction method is mainly based on the element motion equations in the finite element method, as follows:

[0089]

[0090] The stiffness matrix is: [K]=∫ V [B] T [D][B]dv; The mass matrix is: [M]=∫ V [B] T ρ[N]dv; The damping matrix is: [C]=∫ V [B] T γ[N]dv; The equivalent nodal load caused by the volume force acting on the element is: [F]; The elastic force acting on the element is: [K]{q}; The damping force acting on the element is: The inertial force acting on the element is:

[0091] By integrating the above stiffness matrix, damping matrix and mass matrix, we obtain the stiffness matrix [K], damping matrix [C] and mass matrix [M] of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building.

[0092] After integration, the matrix of the entire system is as follows:

[0093]

[0094] Where q1 represents the displacement of the plant structure unit, q2 represents the displacement of the connecting area unit, and q3 represents the displacement of the pressurized water tank unit. This indicates the speed on the structural unit of the factory building. Indicates the velocity on the connected region unit. This indicates the speed on the pressurized water tank unit. This represents the acceleration on the structural unit of the factory building. This represents the acceleration on the connected region element. This indicates the acceleration on the pressurized water tank unit.

[0095] F1 represents the equivalent nodal load caused by the volume force acting on the structural unit of the factory building;

[0096] F2 represents the equivalent nodal load caused by the volume force acting on the connected region element;

[0097] F3 represents the equivalent nodal load caused by the volume force acting on the pressurized water tank unit.

[0098] The finite element software ANSYS extracts the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system and generates a COO file suitable for earthquake analysis software ACS SASSI.

[0099] Step 4: The earthquake ACS SASSI analysis software calls up the extracted stiffness matrix [K], damping matrix [C] and mass matrix [M] of the entire system to form an analysis model of the superstructure of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building;

[0100] In other words, the ACS SASSI analysis software calls the COO files of the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system, and uses the HOUSEFSA module in the ACS SASSI analysis software to form an analysis model of the superstructure of the entire system that considers the coupling effect between the pressurized water tank and the nuclear island building.

[0101] The ACS SASSI analysis software uses the spatial substructure method to handle related issues in SSI analysis. The superstructure is a finite element model, the foundation soil is assumed to be horizontally infinitely layered, and the viscoelastic soil layer lies beneath a uniform elastic half-space. The complex frequency response analysis method is used for seismic response analysis.

[0102] Step 5: Based on the analysis model, add soil layer parameters, seismic input, and the interaction points between the two to conduct seismic response analysis of the nuclear island plant.

[0103] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0104] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing the seismic response of a nuclear island building considering the coupling effect of pressurized water tanks with complex support structures, characterized in that, include: Step 1: Use the finite element software ANSYS to complete the finite element model of the nuclear island plant structure and the pressurized water tank respectively, and then combine the two models into one model; Step 2: Process the connection area between the splicing model and the pressurized water tank to form a coupled model of the pressurized water tank and the nuclear island building; Step 3: Using the finite element software ANSYS, the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building are obtained through the macro commands compiled. Step 4: The earthquake ACS SASSI analysis software calls up the extracted stiffness matrix [K], damping matrix [C] and mass matrix [M] of the entire system to form an analysis model of the superstructure of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building; Step 5: Based on the analysis model, add soil layer parameters, seismic input, and the interaction points between the two to conduct seismic response analysis of the nuclear island plant.

2. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... In step 1, the finite element model of the pressurized water tank is simplified.

3. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 2, is characterized in that... The finite element model of the pressurized water tank includes a main body of the pressurized water tank, with multiple supports connected in the middle of the pressurized water tank and evenly distributed along the circumference of the pressurized water tank. Each support is provided with bolt holes for anchor bolts to pass through. A ring wall groove is opened in the ring wall groove, and the support is set in the ring wall groove. Anchor bolts embedded in the bottom surface of the ring wall groove pass through the bolt holes on the support. An upper tie rod bracket and a lower tie rod bracket are also provided on the ring wall. The upper tie rod is connected to the upper part of the pressurized water tank, and the other end of the upper tie rod is hinged to the upper tie rod bracket. One end of the lower tie rod is connected to the lower part of the pressurized water tank, and the other end of the lower tie rod is hinged to the lower tie rod bracket.

4. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 3, is characterized in that... The simplified approach is as follows: only the main structure of the pressurized water tank is considered; and a simple support structure is used to replace the internal support structure and its connections of the pressurized water tank to ensure that the mass and rigidity of the pressurized water tank remain unchanged. The nonlinear contact problem between the lug and the wall pier, characterized by only compression and no tension, is simplified.

5. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... Step 2 specifically includes: The surface-to-surface connections of the finite element models of the nuclear island plant structure and the pressurized water tank are transformed into point-to-point connections. By converting the local area of ​​the nuclear island plant supporting the pressurized water tank into a solid element model, a mesh design is formed to realize the mutual transfer of loads between the pressurized water tank and the plant structure, thereby forming a local coupling model of the pressurized water tank and the plant structure.

6. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... The method for converting surface-to-surface connections into point-to-point connections is as follows: Multi-point constraint equations are used to establish coupled connections between surfaces and points, and then constraint equilibrium equations are used to establish coupled connections between points, thus achieving the conversion of the connection method, as shown in the following equation: Multi-point constraint equations: Among them U i Let U be the degree of freedom of node i (the node at the point). j n is the degree of freedom of the master node j (nodes on the surface), and n is the number of coupled nodes on the surface; C j The weighting coefficient for the coupling connection of the master node is a function of the distance between the master node and the slave node and the load distribution of different nodes, and the value range is (-1, 1). Among them U i Let U be the degree of freedom of node i (the node at the point). j n is the degree of freedom of the master node j (nodes on the surface), and n is the number of coupled nodes on the surface; C j The weighting coefficient for the coupling connection of the master node is a function of the distance between the master node and the slave node and the load distribution of different nodes, and the value range is (-1, 1). CD is a constant and must satisfy the force and displacement equilibrium equations of the master node and slave node.

7. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... The extraction method is mainly based on the element motion equations in the finite element method, as follows: The stiffness matrix is: [K]=∫ V [B] T [D][B]dv; The mass matrix is: [M]=∫ V [B] T ρ[N]dv; The damping matrix is: [C]=∫ V [B] T γ[N]dv; The equivalent nodal load caused by the volume force acting on the element is: [F]; The elastic force acting on the element is: [K]{q}; The damping force acting on the element is: The inertial force acting on the element is:

8. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 7, is characterized in that... Step 3 specifically includes: In ANSYS software, the stiffness matrix [K] of the building structure is extracted using macro commands. 11 [ ], damping matrix [C1] and mass matrix [M1], stiffness matrix of the connecting region [K 22 [ ], damping matrix [C2] and mass matrix [M2], and pressure tank stiffness matrix [K 33 [ ], damping matrix [C3] and mass matrix [M3], local stiffness [K] between the plant structure and the connecting area 12 ] and [K 21 ] and the local stiffness [K] between the pressurized water tank and the connecting area 23 ] and [K 32 By integrating the above stiffness matrix, damping matrix, and mass matrix, we obtain the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system considering the coupling effect between the pressurized water tank and the nuclear island building. The matrices of the entire system are as follows: Where q1 represents the displacement of the plant structure unit, q2 represents the displacement of the connecting area unit, and q3 represents the displacement of the pressurized water tank unit. This indicates the speed on the structural unit of the factory building. Indicates the velocity on the connected region unit. This indicates the speed on the pressurized water tank unit. This represents the acceleration on the structural unit of the factory building. This represents the acceleration on the connected region element. This indicates the acceleration on the pressurized water tank unit. F1 represents the equivalent nodal load caused by the volume force acting on the structural unit of the factory building; F2 represents the equivalent nodal load caused by the volume force acting on the connected region element; F3 represents the equivalent nodal load caused by the volume force acting on the pressurized water tank unit.

9. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... In step 3, the finite element software ANSYS extracts the stiffness matrix [K], damping matrix [C], and mass matrix [M] of the entire system and generates a COO file suitable for earthquake ACS SASSI analysis software.

10. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... In step 4, the COO files of the stiffness matrix [K], damping matrix [C] and mass matrix [M] of the entire system are called, and the HOUSEFSA module in the ACS SASSI analysis software is used to form an analysis model of the superstructure of the entire system that considers the coupling effect between the pressurized water tank and the nuclear island building.

11. The seismic response analysis method for nuclear island plant buildings considering the coupling effect of pressurized water tanks with complex support structures, as described in claim 1, is characterized in that... The ACS SASSI analysis software uses the spatial substructure method to handle related issues in SSI analysis. The superstructure is a finite element model, the foundation soil is assumed to be horizontally infinitely layered, and the viscoelastic soil layer lies beneath a uniform elastic half-space. The complex frequency response analysis method is used for seismic response analysis.

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