Anti-seismic strength checking method for nuclear power station pipeline support hanger

Abstract

The invention provides an anti-seismic strength checking method for a nuclear power station pipeline support hanger. The anti-seismic strength checking method comprises the following steps: S1, simplifying a stress schematic diagram of the support hanger; s2, a free end point A of the support hanger, any point B on the support hanger and a fixed end point C of the support hanger are defined, the point A is subjected to the action of force FAx, FAy and FAz, and the point B is subjected to the action of force FBx, FBy and FBz; s3, calculating a normal stress sigma Ax corresponding to the force FAx at the point C, and calculating bending stresses sigma Ay and sigma Az corresponding to bending moments generated by the force FAy and the force FAz at the point C; calculating the stress of the force of the point A at any point on the section of the fixed end where the point C is located; s4, calculating the stress of the force borne by the point B at any point on the section of the fixed end where the point C is located; s5, calculating the stress of the point A and the point B acting on any point on the section of the fixed end where the point C is located; and S6, judging whether the support hanger passes the anti-seismic strength check or not according to a calculation result. The checking method is high in calculation speed, capable of reducing repeated work, high in checking efficiency and universal in applicability.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power plant design, and in particular relates to a method for checking the seismic strength of pipeline supports and hangers of a nuclear power plant. Background Art

[0002] Supports and hangers are one of the most commonly used parts in nuclear power plants, supporting the pipelines, valves, etc. of various systems in nuclear power plants. Supports and hangers must not only ensure the support force for pipelines during normal operation of the nuclear power plant, but also consider whether the supports and hangers will deform, bend, become unstable, crack, or even break under earthquake conditions. The design and installation of supports and hangers inside nuclear power plants are complex and are subject to installation space restrictions, and later maintenance issues must also be considered. In order to ensure that the supports and hangers have sufficient support force under earthquake conditions and maintain the normal operation of the nuclear power plant piping system, the strength of the relevant supports and hangers must also be checked when the piping system is checked.

[0003] The existing support and hanger verification method is to model and calculate each support and hanger through the finite element method, and compare it with the relevant verification standards. In addition, there are many pipelines and supports and hangers inside the nuclear power plant, and the pipelines and equipment affect each other. If the strength verification fails, it is necessary to adjust the supports and hangers or the installation position for recalculation. Not only is the workload large, but it can also affect the project progress in serious cases. Based on this, it is necessary to design a hanger strength verification method that is more efficient and can reduce the workload. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for checking the seismic strength of nuclear power plant pipeline supports and hangers in view of the above-mentioned deficiencies in the prior art. The method has fast calculation speed, can reduce repetitive work, has high checking efficiency, and is generally applicable.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for checking the seismic strength of pipeline supports and hangers of a nuclear power plant, characterized in that it comprises the following steps:

[0006] S1. Establish a nuclear power plant piping calculation model and a support and hanger model based on the three-dimensional model of the plant, obtain a force diagram of the support and hanger based on the nuclear power plant piping calculation model and the support and hanger model, and simplify the force diagram of the support and hanger in three-dimensional space;

[0007] S2. According to the simplified force diagram of the support and hanger in three-dimensional space, force analysis is performed, and point A at the free end of the support and hanger, point B at any point on the support and hanger, and point C at the fixed end of the support and hanger are defined. Point A is subjected to force F in three-dimensional space. Ax 、F Ay 、F Az Point B is subject to force F in three-dimensional space. Bx 、F By 、FBz The role of;

[0008] S3. Perform force analysis on point A and calculate force F Ax Normal stress σ at point C Ax , calculation force F Ay 、F Az The bending moment M at point C Ay 、M Az , and calculate the bending moment M Ay 、M Az The bending stress σ corresponding to point C Ay and σ Az ; According to the principle of stress superposition, calculate the stress of any point on the fixed end section where point C is located due to the force applied to point A;

[0009] S4. Perform force analysis on point B. Similar to S3, calculate the force F on point B. Bx 、F By 、F Bz The stress at any point on the fixed end section at point C;

[0010] S5. According to the superposition principle, calculate the stress σ of points A and B acting together at any point on the fixed end section where point C is located, and the maximum stress σ of points A and B at any point on the fixed end section where point C is located. max ;

[0011] S6. Determine whether the seismic strength of the support and hanger has passed the verification based on the calculation results.

[0012] Preferably, the support and hanger in S1 is a double-tube clamp support and hanger.

[0013] Preferably, in S3, the force F Ax The effect on the support bracket is stretching, then F Ax Normal stress at point C:

[0014] Where A represents the cross-sectional area of ​​the support bracket;

[0015] F Ay and F Az At point C, it is curved. Ay and F Az The result of the combination is oblique bending, then F Ay and F Az The bending moment M generated at point C Ay 、M Az They are:

[0016] M Ay =F Az ·L

[0017] MAz =F Ay ·L;

[0018] Where L is the length of the support bracket and is related to the bending moment M Ay and M Az The corresponding bending stresses are:

[0019]

[0020] Among them, I y and I z They represent the moments of inertia when the neutral axis z and y are the cross section of the beam relative to the neutral axis, and z and y represent the coordinates of any point on the fixed end section where point C is located on the yz plane.

[0021] Preferably, the superposition principle is specifically: the response caused by multiple loads acting on the structure simultaneously is equal to the algebraic sum of the responses caused by each load acting on the structure alone;

[0022] Then the stress σ acting at point A on any point on the fixed end section where point C is located is Ax , σ Ay , σ Az Add the algebraic values ​​of

[0023]

[0024] Among them, the maximum stress of the force on point A at any point on the fixed end section where point C is located is:

[0025]

[0026] Among them, W y and W z are the bending section moduli of the y-axis and z-axis respectively.

[0027] Preferably, in S4, the force F Bx The effect on the support bracket is stretching, then F Bx Normal stress at point C:

[0028]

[0029] Where A represents the cross-sectional area of ​​the support bracket;

[0030] The force F at point B By 、F Bz The bending moment at any point on the fixed end section at point C is:

[0031] M By =F Bz (L-L1)

[0032] MBz =F By (L-L1);

[0033] Among them, L1 represents the distance between points A and B;

[0034] Bending moment M By and M Bz The resulting stresses are:

[0035]

[0036] Among them, I y and I z They represent the moments of inertia when the neutral axis z and y are the cross-section of the beam with respect to the neutral axis, respectively. z and y represent the coordinates of any point on the fixed end cross-section where point C is located on the yz plane.

[0037] Then the force on point B is the stress at any point on the fixed end section where point C is located:

[0038]

[0039] The maximum stress of the force on point B at any point on the fixed end section where point C is located is:

[0040]

[0041] Preferably, in S5, according to the superposition principle, the stress at any point on the fixed end cross section where point C is located at point A and point B is:

[0042]

[0043] The maximum stress at any point on the fixed end section of point A and point B at point C is:

[0044]

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] 1. The present invention can obtain the verification result of the support and hanger more quickly, eliminating the modeling and solution process, and is more friendly to the verification of batches of support and hanger. If the verification fails, the steel type can be replaced, which is convenient, fast, safe and reliable.

[0047] 2. Considering the limitation of installation space, it is inevitable to install multiple pipelines on one support and hanger. The present invention can simultaneously perform verification calculations on the support and hanger on which multiple pipelines are installed, which can save modeling and calculation time, reduce duplication of work, and improve work efficiency.

[0048] 3. The present invention is based on theoretical mechanics and material mechanics theory, simplifies the pipeline support and hanger, analyzes the force and establishes a solution formula, and has universal applicability. By changing the existing calculation parameters, including the length or section of the steel section, it can not only be applied to the verification of the support and hanger of the nuclear power plant, but also more similar calculation and analysis can be further derived.

[0049] The present invention is further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a partial three-dimensional model of a nuclear power plant in the present invention (the blue part is the support bracket).

[0051] Figure 2 It is a schematic diagram of the double-pipe clamp support hanger structure in the present invention.

[0052] Figure 3 It is the calculation model of the double-pipe clamp support hanger structure in the present invention.

[0053] Figure 4 It is a general force diagram of the double-tube clamp hanger in the present invention.

[0054] Figure 5 It is a force diagram of an I-beam double-tube clamp hanger in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0055] Finite element calculation is currently used to check the seismic strength of the supports and hangers on the nuclear power pipelines in nuclear power plants. However, the modeling is time-consuming and labor-intensive, and the verification results cannot be given in time. Based on this, this embodiment designs a new method for checking the seismic strength of the supports and hangers. The method first performs the following calculations on the pipelines and supports and hangers in the nuclear power plant: Figure 1 The three-dimensional modeling shown, Figure 1 The blue part is the support bracket, and the yellow part is the pipeline. Taking the double pipe clamp bracket used to support the double pipeline in the model as an example, the schematic diagram of the double pipe clamp bracket structure is as follows: Figure 2 As shown, according to Figure 2 The calculation model of the double-tube bracket structure is obtained (such as Figure 3 As shown in the figure, the support force of the double-pipe bracket structure is extracted through the pipeline calculation software based on the calculation model, and the simplified schematic diagram of the support force in three-dimensional space is shown in the figure. Figure 4 In the specific on-site environment, the double-tube bracket is a No. 10 hot-rolled I-beam bracket, so the simplified bracket force diagram in three-dimensional space is as follows Figure 5 shown.

[0056] This embodiment verifies the seismic strength of the double-tube bracket, and the verification method includes the following steps:

[0057] S1. Basis Figure 1 The three-dimensional plant model shown in the figure establishes a pipeline calculation model and a bracket model. The pipeline calculation model contains basic information such as the location information, size information, and material information of the target pipeline for verification. Based on the nuclear power plant pipeline calculation model and bracket model, a simplified force diagram of the bracket is obtained as shown in Figure 3 or Figure 5 As shown;

[0058] S2, based on Figure 3 or Figure 5 The simplified bracket shown in the figure is subjected to force analysis in three-dimensional space. Point A at the free end of the bracket, point B at any point on the bracket, and point C at the fixed end of the bracket are defined. Point A is subjected to force F Ax 、F Ay 、F Az Point B is subject to force F Bx 、F By 、F Bz The total length of the I-beam support is L, and the distance between points AB is L1.

[0059] S3. Perform force analysis on point A. Force F Ax The effect on the bracket is stretching, then F Ax Normal stress at point C:

[0060]

[0061] Wherein, A represents the cross-sectional area of ​​the I-beam support.

[0062] F Ay and F Az At point C, it is curved. Ay and F Az The result of the combination is oblique bending, then F Ay and F Az The bending moments generated at point C are:

[0063] M Ay =F Az ·L

[0064] M Az =F Ay ·L;

[0065] Where L is the length of the bracket and the bending moment M Ay and M Az The corresponding bending stresses are:

[0066]

[0067] Among them, I y and I zThey represent the moments of inertia when the neutral axis z and y are the cross section of the beam relative to the neutral axis, and z and y represent the coordinates of any point on the fixed end section where point C is located on the yz plane.

[0068] If only the force at point A is considered, according to the algebraic sum principle that the response caused by multiple loads acting on the structure at the same time is equal to the response caused by each load acting on the structure alone, the stress σ at point A acting on any point on the fixed end section at point C is Ax , σ Ay , σ Az The algebraic addition of

[0069]

[0070] The maximum stress of the force at point A on the fixed end section at point C is:

[0071]

[0072] Among them, W y and W z are the bending section moduli of the y-axis and z-axis respectively.

[0073] S4. Perform force analysis on point B. Consider only the force on point B and calculate the stress at any point on the fixed end section where point C is located. The force F Bx The effect on the support bracket is stretching, then F Bx Normal stress at point C:

[0074]

[0075] Where A represents the cross-sectional area of ​​the I-beam support;

[0076] The bending moment of the force at point B at any point on the fixed end section where point C is located is:

[0077] M By =F Bz (L-L1)

[0078] M Bz =F By (L-L1);

[0079] Bending moment M By and M Bz The resulting stresses are:

[0080]

[0081] Then the force on point B is the stress at any point on the fixed end section where point C is located:

[0082]

[0083] The maximum stress of the force on point B at any point on the fixed end section where point C is located is:

[0084]

[0085] S5. According to the superposition principle, considering the overall force, the stress of any point on the fixed end section where point C is located is caused by the joint action of points A and B:

[0086]

[0087] The maximum stress at point C acting on points A and B is:

[0088]

[0089] S7. Perform finite element calculation and formula calculation of this embodiment on the bracket respectively. The corresponding basic parameters are: I-beam is GB / T706-2008 No. 10 steel, length L = 425mm; distance between AB L1 = 125mm, F Ax =965N, F Ay =2286N,F Az =744N, F Bx =626N,F By =2063N,F Bz =476N; Section coefficient W y =49000mm 3 , W z =9720mm 3 , cross-sectional area A = 1434.5 mm 2 .

[0090] The calculation results of the formula of this embodiment are shown in Table 1, and the comparison between the finite element calculation results and the calculation results of the formula of this embodiment is shown in Table 2.

[0091] Table 1 Calculation results of the formula in this embodiment

[0092]

[0093] Table 2 Comparison of finite element calculation results and formula calculation results of this embodiment

[0094] Theoretical calculation (MPa) Finite element calculation (MPa) error <![CDATA[σ Amax ]]> 107.08 111.17 3.82％ <![CDATA[σ Bmax ]]> 67.02 59.98 10.52％ <![CDATA[σ max ]]> 174.10 170.78 1.91％

[0095] Through formula calculation and finite element calculation method, single-point and multi-point force analysis of the bracket is carried out. Compared with the finite element calculation method, the formula calculation method can save time, obtain results faster, and give designers faster feedback.

[0096] There are some differences between the finite element calculation model and the actual standard steel section. The data calculated by theoretical calculation is derived from the national standard GB / T 706-2008, which is in line with the actual engineering practice. The finite element error comes from many aspects such as the simplification of the geometric model, the meshing method, and the solver accuracy. In actual engineering problems, the finite element result error within 15% is considered reasonable.

[0097] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for checking the seismic strength of pipeline supports and hangers in a nuclear power plant, characterized in that: The following steps are involved: S1. Establish a nuclear power plant piping calculation model and a support and hanger model based on the three-dimensional model of the plant, obtain a force diagram of the support and hanger based on the nuclear power plant piping calculation model and the support and hanger model, and simplify the force diagram of the support and hanger in three-dimensional space; S2. According to the simplified force diagram of the support and hanger in three-dimensional space, force analysis is performed. The free end of the support and hanger is defined as point A, any point on the support and hanger is defined as point B, and the fixed end of the support and hanger is defined as point C. Point A is subjected to force F in three-dimensional space. Ax 、F Ay 、F Az Point B is subject to force F in three-dimensional space. Bx 、F By 、F Bz The role of; S3. Perform force analysis on point A and calculate force F Ax Normal stress σ at point C Ax , calculation force F Ay 、F Az The bending moment M at point C Ay 、M Az , and calculate the bending moment M Ay 、M Az The bending stress σ corresponding to point C Ay and σ Az ; According to the principle of stress superposition, calculate the stress of any point on the fixed end section where point C is located due to the force applied to point A; S4. Perform force analysis on point B. Similar to S3, calculate the force F on point B. Bx 、F By 、F Bz The stress at any point on the fixed end section at point C; S5. According to the superposition principle, calculate the stress of points A and B acting together at any point on the fixed end section where point C is located, and the maximum stress of points A and B at any point on the fixed end section where point C is located; S6. Determine whether the seismic strength of the support and hanger has passed the verification based on the calculation results.

2. A method for checking the seismic strength of pipeline supports and hangers in a nuclear power plant according to claim 1, characterized in that: The S1 middle support hanger is a double-tube clamp support hanger.

3. A method for checking the seismic strength of pipeline supports and hangers in a nuclear power plant according to claim 1, characterized in that: In S3, the force F Ax The effect on the support bracket is stretching, then F Ax Normal stress at point C: Where A represents the cross-sectional area of ​​the support bracket; F Ay and F Az At point C, it is curved. Ay and F Az The result of the combination is oblique bending, then F Ay and F Az The bending moment M generated at point C Ay 、M Az They are: M Ay =F Az ·L M Az =F Ay ·L; Where L is the length of the support bracket and is related to the bending moment M Ay and M Az The corresponding bending stresses are: Among them, I y and I z They represent the moments of inertia when the neutral axis z and y are the cross section of the beam relative to the neutral axis, and z and y represent the coordinates of any point on the fixed end section where point C is located on the yz plane.

4. A method for checking the seismic strength of pipeline supports and hangers in a nuclear power plant according to claim 3, characterized in that: The superposition principle is specifically: the response caused by multiple loads acting on the structure at the same time is equal to the algebraic sum of the responses caused by each load acting on the structure alone; Then the stress σ acting at point A on any point on the fixed end section where point C is located is Ax , σ Ay , σ Az The algebraic addition of is: Among them, the maximum stress of the force on point A at any point on the fixed end section where point C is located is: Among them, W y and W z are the bending section moduli of the y-axis and z-axis respectively.

5. A method for checking the seismic strength of pipeline supports and hangers in a nuclear power plant according to claim 4, characterized in that: In S4, the force F Bx The effect on the support bracket is stretching, then F Bx Normal stress at point C: Where A represents the cross-sectional area of ​​the support bracket; The force F at point B By 、F Bz The bending moment at any point on the fixed end section at point C is: M By =F Bz ·(L-L1) M Bz =F By ·(L-L1); Among them, L1 represents the distance between points A and B; Bending moment M By and M Bz The resulting stresses are: Among them, I y and I z They represent the moments of inertia when the neutral axis z and y are the cross-section of the beam with respect to the neutral axis, respectively. z and y represent the coordinates of any point on the fixed end cross-section where point C is located on the yz plane. Then the force on point B is the stress at any point on the fixed end section where point C is located: The force on point B is then the maximum stress at any point on the fixed end section where point C is located:

6. A method for checking the seismic strength of pipeline supports and hangers in a nuclear power plant according to claim 5, characterized in that: In S5, according to the superposition principle, the stress of any point on the fixed end section where point C is located is jointly exerted by points A and B: The maximum stress at any point on the fixed end section where point C is located, caused by the combined effect of points A and B:

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