Prediction method for rebound resilience of small-size O-shaped metal sealing ring

Abstract

The invention discloses a method for predicting the rebound resilience of a small-size O-shaped metal sealing ring, which comprises the following steps of: performing a standard uniaxial tensile test on a material of an O-shaped ring sample to obtain a uniaxial stress-strain relation curve; fitting a uniaxial stress-strain relation curve by utilizing a Hollomon model formula; obtaining the three-dimensional size of the O-shaped ring, and calculating the compression displacement h when the compression ratio is lambda; establishing a corresponding relation between the compression displacement h and the compression resilience force F to obtain a compression resilience force Fm when the compression ratio is lambda; acquiring an unloading slope Se corresponding to unloading at the position where the compression resilience force is Fm, and calculating a resilience value he; and calculating the springback ratio H by using the springback value he. According to the method, finite element analysis calculation is combined, the corresponding relation between the rebound resilience parameter of the O-shaped ring sample and the loaded compression ratio is established, finite element analysis is combined, the rebound resilience parameter of the small-size O-shaped ring sample can be effectively obtained, and therefore the excellent sealing performance of the sealing ring sample is accurately reflected, and the method is suitable for large-range ductile metal materials.

Description

Technical Field

[0001] The invention relates to the technical field of prediction of the resilience performance of sealing parts, and in particular to a method for predicting the resilience performance of a small-sized O-type metal sealing ring. Background Art

[0002] O-ring metal ring sealing technology is widely used in flange sealing structures of pressure vessels of large engineering structures (such as nuclear reactors). The O-ring seal is located between the upper and lower flanges. The O-ring sample is pre-compressed to a certain extent during pre-assembly. After assembly, the rebound characteristics of the ring sample will produce continuous rebound force, thus achieving long-term stable sealing of the sealing structure. For example, for the pressure vessel of a nuclear reactor, the materials stored inside contain certain radioactive substances, which are first-level safety equipment and their safety is extremely important. Long-term stable sealing performance is an important guarantee to prevent the leakage of contaminants in the container. The rebound performance parameter of the O-ring is a key parameter to test the reliability of the seal, which is mainly manifested in the corresponding relationship between the rebound ratio and the compression ratio, that is, how much rebound a ring sample of a certain diameter will produce under a certain compression ratio.

[0003] Researchers have conducted extensive research on this. Cai Lixun (Cai Lixun, Ye Yuming, Zuo Guo. High-temperature flattening elastic-plastic behavior of Inconel 718 alloy O-rings [J]. Journal of Shanghai Jiaotong University, 2005, 39(5): 818-822.) et al. conducted detailed experimental test research on the factors affecting the rebound performance of Inconel 718 alloy O-rings; Zheng Liangang (Zheng Liangang, Zhang Liping, Yang Yu. Sealing analysis technology for reactor pressure vessels [J]. Nuclear Power Engineering, 2009, 30(3): 4-6.) et al. conducted a numerical simulation study on the three-dimensional coupled thermal elastic-plastic contact of O-type sealing structures.

[0004] The above research is mainly based on test data, or numerical simulation analysis results, and then regression statistics to form empirical formulas. It is only applicable to the prediction of the rebound performance of a small part of materials within a small range of compression ratios, and does not have good universality. It is inconvenient for engineering applications and the prediction accuracy is not high.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The problem with the prior art is that the existing research on the rebound performance of O-ring seals is based on test data or numerical simulation analysis results, which is only applicable to the prediction of the rebound performance of a small part of materials within a small range of compression ratios and does not have good universality. The present invention provides a method for predicting the rebound performance of small-sized O-ring metal sealing rings. Combined with finite element analysis and calculation, a corresponding relationship between the rebound performance parameters of the O-ring sample and the loaded compression ratio is established. Combined with finite element analysis, the rebound performance parameters of the small-sized O-ring samples can be effectively obtained, thereby accurately reflecting the excellent sealing performance of the sealing ring samples, and being suitable for a wide range of ductile metal materials.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for predicting the rebound performance of a small-sized O-type metal sealing ring comprises the following steps:

[0009] S1, performing a standard uniaxial tensile test on the raw material of the O-ring sample to obtain a uniaxial stress-strain curve of the raw material;

[0010] S2, using the Hollomon model formula to fit the uniaxial stress-strain relationship curve of the O-ring raw material;

[0011] S3, obtaining the three-dimensional dimensions of the O-ring, and calculating the compression displacement h when the compression ratio of the O-ring is λ;

[0012] S4, the corresponding relationship between the compression displacement h and the compression rebound force F is established, and the corresponding compression rebound force F when the compression ratio is λ is obtained m ;

[0013] S5, obtain the compression rebound force F m Unloading at the corresponding unloading slope S e , calculate the corresponding rebound amount h e ;

[0014] S6, the rebound amount h calculated using S5 e , calculate the corresponding rebound ratio H when the compression ratio is λ.

[0015] In a specific embodiment, in step S2, the uniaxial stress σ-strain ε relationship curve of the O-ring raw material is fitted using the Hollomon model formula to obtain the Hollomon model parameters elastic modulus E, nominal yield strength σ y , strain hardening exponent n;

[0016] in,

[0017] In a specific embodiment, in step S3, the three-dimensional dimensions include the outer diameter D, thickness t and width L of the O-ring;

[0018] The compression ratio of the O-ring is known to be λ, and the corresponding compression displacement h is calculated by the following formula:

[0019] h=Dλ formula (2).

[0020] In a specific embodiment, in step S4, F m The calculation formula is as follows:

[0021]

[0022] In the formula, take the effective length h * =D, the effective area is A * , π is the ratio of pi; k1, k2, k3, k4 are calibration parameters calculated by numerical analysis.

[0023] In a specific embodiment, in step S5, the rebound amount h e The calculation formula is as follows:

[0024]

[0025] Where k5 is the calibration parameter calculated by numerical analysis.

[0026] In a specific implementation, in step S5, the calculation formula of the rebound ratio H corresponding to the compression ratio λ is as follows:

[0027]

[0028] In a specific implementation, in step S4, the calculation method of calibration parameters k1, k2, k3, k4 is as follows:

[0029] (1) Establish a finite element analysis model with the model dimensions of outer diameter D, thickness, and width L, perform mesh division and type selection, and simulate and analyze the model metal compression loading and unloading;

[0030] (2) Use the Hollomon model as the material performance parameter input, set the elastic modulus E, nominal tensile strength σ y , 5 strain hardening exponents n, corresponding to a variety of materials, can be calculated by finite element to extract the load and displacement data of the loading and unloading process;

[0031] (3) The load-displacement curve of the extracted loading section is non-dimensionalized according to the following formula, and then the elastic-plastic section of the load-displacement curve after dimensionless processing is fitted using a power rate function to obtain the coefficient C corresponding to the series. i and m i (i=1, 2, 3, 4, 5);

[0032]

[0033] (4) Substitute the C obtained in (3) i , m i (i=1, 2, 3, 4, 5), and the parameters k1, k2, k3, k4 can be calibrated and obtained by fitting according to the following formula;

[0034]

[0035] In a specific implementation, in step S5, the calculation method of the calibration parameter k5 is as follows:

[0036] Use a linear function to fit the unloading straight line segment of the load-displacement curve to obtain the corresponding unloading slope S e ;

[0037] F=S e h formula (8);

[0038] The fitted S e Substituting into the following formula, the parameter k5 can be calculated

[0039]

[0040] In a specific embodiment, the material of the O-type metal sealing ring is a large-range continuous metal material with a yield strength of 100 MPa to 1000 MPa.

[0041] In a specific embodiment, the residual displacement h after unloading is extracted from the load-displacement curve. r , the actual rebound h is calculated by subtracting the residual displacement from the total compression displacement e ', calculate the actual rebound ratio H t , which is used for subsequent comparison with the prediction results. The calculation formula is as follows:

[0042]

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] 1. A prediction method for the rebound performance of a small-sized O-type metal sealing ring provided in an embodiment of the present invention, combined with finite element analysis calculation, establishes a corresponding relationship between the rebound performance parameter (rebound ratio) of the O-type ring sample and the loaded compression ratio, and combined with finite element analysis, can effectively obtain the rebound performance parameter of the small-sized O-ring sample, thereby accurately reflecting the excellent sealing performance of the sealing ring sample, and is suitable for a wide range of ductile metal materials;

[0045] 2. A method for predicting the rebound performance of a small-sized O-type metal sealing ring provided in an embodiment of the present invention combines theoretical formulas with numerical analysis. No experimental test or numerical analysis calculation is required. The rebound amount of the ring sample under a specified compression amount can be simply and effectively calculated by directly using the provided formulas and parameters with given material performance parameters, sample size and given compression ratio.

[0046] 3. A method for predicting the rebound performance of a small-sized O-ring metal sealing ring provided in an embodiment of the present invention provides a prediction formula and parameters for the rebound performance of a ring sample component in an engineering project. No experimental test is required, which reduces the test cost. The prediction result is accurate and reliable. It has great engineering application value for small-sized O-ring structures or pipeline structures in engineering projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A schematic diagram of the O-ring structure provided by an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of a compression load-displacement curve provided by an embodiment of the present invention;

[0050] Figure 3 A numerical analysis model provided by an embodiment of the present invention;

[0051] Figure 4 A comparison chart of the rebound performance prediction results provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0053] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to those of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other embodiments, in order to avoid obscuring the present invention, well-known materials or methods are not specifically described.

[0054] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a method for predicting the resilience performance of a small-sized O-type metal sealing ring, comprising the following steps:

[0058] S1, performing a standard uniaxial tensile test on the raw material of the O-ring sample to obtain a uniaxial stress-strain curve of the raw material;

[0059] S2, using the Hollomon model formula to fit the uniaxial stress σ-strain ε relationship curve of the O-ring raw material, and obtain the Hollomon model parameters elastic modulus E, nominal yield strength σ y , strain hardening exponent n;

[0060] in,

[0061] S3, obtain the three-dimensional dimensions of the O-ring, such as Figure 1 As shown, it includes the outer diameter D, thickness t and width L of the O-ring; it is known that the compression ratio of the O-ring is λ, and the corresponding compression displacement h is calculated by the following formula;

[0062] h=Dλ Formula (2);

[0063] S4, based on the elastic-plastic theory, the corresponding relationship between the compression displacement h and the compression rebound force F is established. The curve of the compression displacement h and the compression rebound force F is as follows: Figure 2 As shown in the figure, the corresponding compression rebound force F when the compression displacement is h can be predicted, and the compression displacement h and the tensile performance parameters E, σ y Substituting , n into the following formula, the corresponding compression rebound force F when the compression ratio is λ can be calculated m :

[0064]

[0065] In the formula, take the effective length h * =D, effective area is A * , π is the circumference of a circle; k1, k2, k3, k4 are calibration parameters calculated by numerical analysis;

[0066] S5, obtain the compression rebound force F m Unloading at the corresponding unloading slope S e , the calculation formula is as follows:

[0067]

[0068] Then the compression rebound force F obtained by S4 m Substitute and calculate the corresponding rebound amount h e ; In the formula, k5 is the calibration parameter calculated by numerical analysis;

[0069] S6, the rebound amount h calculated using S5 e Substitute the following formula: The rebound ratio H corresponding to the compression ratio λ is calculated.

[0070] In a specific implementation, in step S4, the calculation method of calibration parameters k1, k2, k3, k4 is as follows:

[0071] (1) Figure 3 As shown, a finite element analysis model is established, and the model dimensions are as follows: outer diameter D = 10 mm, thickness t = 1 mm, and width L = 1 m. Reasonable mesh division and type selection are performed, and the upper and lower plates are used to simulate and analyze the metal compression loading and unloading of the model;

[0072] (2) Use the Hollomon model as the material property parameter input, set the elastic modulus E = 200 GPa, and the nominal tensile strength σ y =500MPa, strain hardening exponent n=0.1, 0.2, 0.3, 0.4, 0.5, corresponding to 5 kinds of materials, after completing the finite element calculation, the load and displacement data of the loading and unloading process are extracted;

[0073] (3) The load-displacement curve of the extracted loading section is non-dimensionalized according to the following formula, and then the elastic-plastic section of the load-displacement curve after dimensionless processing is fitted using a power rate function to obtain the coefficient C corresponding to the series. i and m i (i=1, 2, 3, 4, 5);

[0074]

[0075] (4) Substitute the C obtained in (3) i , m i (i=1, 2, 3, 4, 5), and the parameters k1, k2, k3, k4 can be calibrated and obtained by fitting according to the following formula;

[0076]

[0077] In a specific implementation, in step S5, the calculation method of the calibration parameter k5 is as follows:

[0078] Use a linear function to fit the unloading straight line segment of the load-displacement curve to obtain the corresponding unloading slope S e ;

[0079] F=S e h formula (8);

[0080] The fitted S e Substituting into the following formula, the parameter k5 can be calculated:

[0081]

[0082] In a specific implementation, for O-ring samples of other sizes, k1, k2, k3, k4, and k5 can be recalibrated according to the above method.

[0083] In a specific embodiment, the material of the O-type metal sealing ring is a large-range continuous metal material with a yield strength of 100 MPa to 1000 MPa.

[0084] Example 2

[0085] The embodiment of the present invention provides a verification method for predicting the rebound performance of a small-sized O-type metal sealing ring, comprising the following steps:

[0086] (1) Figure 3 As shown in the figure, a finite element analysis model is established, and the model dimensions are as follows: outer diameter D = 10 mm, thickness t = 1 mm, and width L = 1 m; reasonable mesh division and material type selection are performed, and the Hollomon model parameters are set in the analysis software: elastic modulus E = 200 GPa, nominal tensile strength σ y=100~1100MPa, interval 200MPa, strain hardening index n=0.1, 0.2, 0.3, 0.4, 0.5, corresponding to 30 kinds of materials; simulate and analyze the compression loading and unloading of the model metal through the upper and lower plates, fix the lower plate, and apply the displacement load loading and unloading to the O-ring through the upper clamp. The displacement pressure is applied according to the compression ratio. Set the compression ratio λ=10%, then the maximum displacement h=Dλ=1mm. After completing the finite element loading and unloading calculation, extract the load, displacement and other data of the loading and unloading process;

[0087] (2) Extract the residual displacement h after unloading from the load-displacement curve r , the actual rebound amount h can be calculated by subtracting the residual displacement from the total compression displacement e ', and then calculate the real rebound ratio H t , used for subsequent prediction result comparison;

[0088]

[0089] (3) Substituting the total compression displacement h = Dλ into the following formula, the corresponding compression rebound force F when the compression displacement is h can be calculated: m ;

[0090]

[0091] In the formula, the effective length h * =D,A * is the effective area, L is the width of the ring sample, and π is the circumference of a circle; k1, k2, k3, and k4 are calibration parameters, and the calculated values ​​are shown in Table 1;

[0092] (4) The calculated F m Substitute into the following formula to calculate the corresponding rebound amount h e . Then the rebound ratio H is calculated;

[0093]

[0094] Where E is the elastic modulus, k5 is the calibration parameter, and the calculated values ​​are shown in Table 1.

[0095] Table 1 Calibration parameters of rebound performance prediction formula

[0096]

[0097] Compare the springback ratio H obtained by the prediction method of the embodiment of the present invention with the actual springback ratio H obtained by finite element calculation. t ,like Figure 4 As shown, it can be seen that the predicted value is highly correlated with the true value, the prediction effect is good, and the prediction result is accurate and reliable.

[0098] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for predicting the resilience of a small-sized O-type metal sealing ring, characterized in that: The steps include: S1, performing a standard uniaxial tensile test on the raw material of the O-ring sample to obtain a uniaxial stress-strain curve of the raw material; S2, using the Hollomon model formula to fit the uniaxial stress-strain relationship curve of the O-ring raw material; S3, obtaining the three-dimensional dimensions of the O-ring, and calculating the compression displacement h when the compression ratio of the O-ring is λ; S4, establish the corresponding relationship between the compression displacement h and the compression rebound force F, and obtain the corresponding compression rebound force F when the compression ratio is λ m ; S5, obtain the compression rebound force F m Unloading at the corresponding unloading slope S e , calculate the corresponding rebound amount h e ; S6, using the calculated rebound h e , calculate the corresponding rebound ratio H when the compression ratio is λ.

2. The method for predicting the rebound performance of a small-sized O-type metal sealing ring according to claim 1, characterized in that: In step S2, the uniaxial stress σ-strain ε relationship curve of the O-ring raw material is fitted using the Hollomon model formula to obtain the Hollomon model parameters elastic modulus E, nominal yield strength σ y , strain hardening exponent n; in, 3. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 2, characterized in that: In step S3, the three-dimensional dimensions include the outer diameter D, thickness t and width L of the O-ring; The compression ratio of the O-ring is known to be λ, and the corresponding compression displacement h is calculated by the following formula: h=Dλ formula (2).

4. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 3, characterized in that: In step S4, F m The calculation formula is as follows: In the formula, take the effective length h * =D, the effective area is A * , π is the ratio of pi; k1, k2, k3, k4 are calibration parameters calculated by numerical analysis.

5. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 4, characterized in that: In step S5, the rebound amount h e The calculation formula is as follows: Where k5 is the calibration parameter calculated by numerical analysis.

6. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 5, characterized in that: In step S5, the calculation formula of the rebound ratio H corresponding to the compression ratio λ is as follows:

7. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 6, characterized in that: In step S4, the calculation method of calibration parameters k1, k2, k3, k4 is as follows: (1) Establish a finite element analysis model with the model dimensions of outer diameter D, thickness, and width L, perform mesh division and type selection, and simulate and analyze the metal compression loading and unloading of the model; (2) Use the Hollomon model as the material performance parameter input, set the elastic modulus E, nominal tensile strength σ y , 5 strain hardening exponents n, corresponding to a variety of materials, can be calculated by finite element to extract the load and displacement data of the loading and unloading process; (3) The load-displacement curve of the extracted loading section is non-dimensionalized according to the following formula, and then the elastic-plastic section of the load-displacement curve after dimensionless processing is fitted using a power rate function to obtain the coefficient C corresponding to the series. i and m i (i=1, 2, 3, 4, 5); (4) Substitute the C obtained in (3) i , m i (i=1, 2, 3, 4, 5), and the parameters k1, k2, k3, k4 can be calibrated and obtained by fitting according to the following formula; 8. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 6, characterized in that: In step S5, the calculation method of the calibration parameter k5 is as follows: Use a linear function to fit the unloading straight line segment of the load-displacement curve to obtain the corresponding unloading slope S e ; F=S e h formula (8); The fitted S e Substituting into the following formula, the parameter k5 can be calculated 9. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 1, characterized in that: The material of the O-type metal sealing ring is a continuous metal material with a yield strength of 100MPa to 1000MPa.

10. The method for predicting the resilience performance of a small-sized O-type metal sealing ring according to claim 7, characterized in that: Extract the residual displacement h after unloading from the load-displacement curve r , the actual rebound h is calculated by subtracting the residual displacement from the total compression displacement e ', calculate the actual rebound ratio H t , which is used for subsequent comparison with the prediction results. The calculation formula is as follows:

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