A method for rapidly predicting damage of a metal pressure-bearing equipment cylinder under external blast loading

Abstract

The present application relates to the technical field of energy storage and transportation, and discloses a kind of quick prediction method of metal pressure-bearing equipment cylinder damage under external explosion load, comprising the following steps: obtaining the parameters of the metal pressure-bearing equipment to be predicted and the maximum unit area impulse I of external explosion load acting on pressure-bearing equipment;Calculate the deflection angle θ of the cylinder section of pressure-bearing equipment;The cylinder section deflection angle θ obtained by calculation is compared with the preset damage grade criterion, so as to judge the cylinder damage grade of pressure-bearing equipment.The above-mentioned prediction method, the prediction step is based on formula calculation, the calculation process is fast, simple and convenient, without building and solving complex finite element model of pressure-bearing equipment, so as to greatly improve the prediction efficiency, reduce the professional skill requirement and learning cost of engineer, and reduce the technical threshold.

Description

Technical Field

[0001] This invention relates to the field of energy storage and transportation technology, and in particular to a method for rapid prediction of damage to the cylinder of metal pressure-bearing equipment under external explosion load. Background Technology

[0002] Metal pressure vessels are mainly used for storing and transporting gases, liquids, liquefied gases, and other media, and are widely used in industries such as petroleum, chemical, and energy. During service, these pressure vessels face the threat of media combustion and explosion, or shock waves generated by the explosion of nearby other pressure vessels. Existing prediction methods primarily focus on predicting damage to pressure vessels under fatigue, vibration, and corrosion conditions; there are currently no methods for predicting the extent of damage to pressure vessels under explosive loads.

[0003] Currently, methods for assessing the safety of pressure-bearing equipment under transient impact have also been developed. For example, the American Society of Mechanical Engineers (ASME), in ASME BPVC. VIII-2, specifies elastoplastic analysis of pressure-bearing equipment based on numerical simulation, calculating the equivalent plastic strain and forming strain at critical locations, and comparing them with the ultimate triaxial strain for assessment. Furthermore, ASME BPVC.VIII-3 specifies calculating the membrane strain and flexural strain at critical locations of pressure-bearing equipment and converting them into equivalent plastic strain, then comparing them with a given plastic strain limit for assessment. However, these methods suffer from drawbacks such as high implementation difficulty, lengthy processes, difficulties in verifying the reliability of the models, difficulty for engineers to understand, and high learning costs. Summary of the Invention

[0004] Addressing the technical challenges of existing methods for determining the safety of pressure equipment damage, such as high implementation difficulty, lengthy processes, difficulty in verifying model reliability, difficulty for engineers to understand, and high learning costs, this invention provides a rapid prediction method for the damage of metal pressure equipment cylinders under external explosion loads. Compared with existing methods for determining the damage of pressure equipment based on numerical simulation, this method does not require the construction of a finite element model, is easy to implement, fast and simple, and is easy for engineers to understand.

[0005] This invention provides a method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load, comprising:

[0006] A method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load, characterized by comprising the following steps:

[0007] S1: Obtain the parameters of the metal pressure-bearing equipment to be predicted, including at least: cylinder length L, cylinder outer diameter D, cylinder thickness δ, material yield strength σy, and material density ρ; simultaneously, obtain the maximum unit area impulse I of the external explosion load acting on the pressure-bearing equipment;

[0008] S2: Based on the parameters obtained in step S1, calculate the deflection angle θ of the cylinder section of the pressure-bearing equipment using the following formula:

[0009] ;

[0010] S3: Compare the cylinder section deflection angle θ calculated in S2 with the preset damage level criterion to determine the cylinder damage level of the pressure-bearing equipment.

[0011] In some embodiments, the damage level criterion in step S3 is specifically as follows:

[0012] When the calculated deflection angle θ of the cylinder cross section satisfies 0° < θ ≤ 2°, the cylinder is determined to have suffered minor damage.

[0013] When the calculated deflection angle θ of the cylinder section satisfies 2° < θ ≤ 5°, the cylinder is determined to have suffered general damage.

[0014] When the calculated deflection angle θ of the cylinder cross section satisfies 5° < θ ≤ 10°, the cylinder is determined to have suffered significant damage.

[0015] When the calculated deflection angle θ of the cylinder cross section satisfies θ>10°, the cylinder is determined to be severely damaged.

[0016] In some embodiments, the deflection angle θ of the cylinder section is defined as: the angle formed by the axial tangent direction at the connection point between the end cap of the pressure equipment and the cylinder, and the line connecting the connection point and the point of maximum cylinder deflection after the explosion deformation.

[0017] In some embodiments, when the cylinder is determined to have suffered minor damage, its damage state is described as no substantial plastic deformation of the cross section.

[0018] When the cylinder is determined to have suffered general damage, its damage state is described as local yielding, and the overall deformation of the structure is controllable.

[0019] In some embodiments, when the cylinder is determined to have suffered significant damage, its damage state is described as having undergone obvious plastic deformation.

[0020] When the cylinder is determined to be severely damaged, its damage state is described as severe plastic deformation, and the severe plastic deformation is sufficient to cause fracture or support failure.

[0021] In some embodiments, the step of obtaining the maximum impulse per unit area I in step S1 specifically includes: obtaining the explosion energy W of the external explosion load; obtaining the distance R between the explosion source center and the pressure-bearing device; and calculating the maximum impulse per unit area I based on the explosion energy W and the distance R.

[0022] Compared with the prior art, the advantages and positive effects of the present invention are:

[0023] The above-mentioned rapid prediction method for damage to the cylinder of metal pressure equipment under external explosion load is based on formula calculation. The calculation process is fast and simple, and there is no need to build and solve complex finite element models of pressure equipment, which greatly improves the prediction efficiency. At the same time, it reduces the professional skills requirements and learning costs for engineers and lowers the technical threshold.

[0024] Furthermore, the prediction method of this invention is based on the deformation angle of the cylinder of a pressure-bearing device under external explosive loads in the absence of internal pressure, to infer its damage level. This approach fully considers the safety and conservatism principles of engineering applications. Its rationale lies in the fact that, under actual operating conditions, internal pressure increases the overall structural rigidity of the equipment, thereby reducing the cylinder cross-sectional deflection angle θ under the same external explosive load. For conservative considerations, this invention, by calculating the deformation angle of the cylinder under no-internal-pressure conditions, can quickly determine the damage level. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the steps of the rapid prediction method for damage to the cylinder of a metal pressure-bearing device under external explosion load according to the present invention.

[0027] Figure 2 This is a schematic diagram of the cylinder section deflection angle θ in the rapid prediction method for damage to the cylinder of a metal pressure-bearing device under external explosion load according to the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0032] Reference Figures 1-2 This invention provides a rapid prediction method for the damage of the cylinder of a metal pressure-bearing device under external explosion load. This method aims to solve the technical problems of existing technologies, such as complex prediction processes, long calculation times, high requirements for the professional skills of engineers, and the need to construct and verify complex finite element models. This invention achieves rapid, simple, and reliable prediction of the degree of damage through a prediction formula that comprehensively considers the explosion load, equipment geometric parameters, and material properties.

[0033] See Figure 1 A rapid prediction method for damage to the cylinder of metal pressure-bearing equipment under external explosion load includes the following steps:

[0034] S1: Obtain the basic parameters required for prediction. This step is fundamental to making predictions. The basic parameters include two categories: the metal pressure vessel consists of a cylindrical body 1 and end caps 2 connected to both ends of the body.

[0035] Firstly, the structural and material parameters of the metal pressure vessel itself. In this application, the metal pressure vessel includes a cylinder 1 and end caps 2 connected to both ends of the cylinder. The parameters include at least:

[0036] Cylinder length L: The effective length of cylinder 1 of the pressure equipment, in meters (m).

[0037] Outer diameter D of the cylinder: The outer diameter of the cylinder 1 of the pressure equipment, in meters (m).

[0038] Cylinder thickness δ: The wall thickness of cylinder 1 of the pressure equipment, in meters (m).

[0039] Material yield strength σ yYield strength of the metallic materials constituting pressure-bearing equipment, measured in Pascals (Pa). This parameter is a key indicator of a material's resistance to permanent deformation and can usually be found in material handbooks or design documents.

[0040] Material density ρ: The density of the metallic materials that make up the pressure-bearing equipment, expressed in kilograms per cubic meter (kg / m³).

[0041] Second, the load parameters generated by the external explosion, namely the maximum impulse per unit area I acting on the pressure-bearing equipment, in Pascal-seconds (Pa·s).

[0042] S2: Calculate the deflection angle θ of the cylinder section.

[0043] Using all the parameters obtained in step S1, substitute them into the prediction formula to calculate the deflection angle θ of the cylinder section. The formula is:

[0044] ;

[0045] In this application, as Figure 2 As shown, the deflection angle θ of the cylinder section is physically defined as: the angle formed by the axial tangent direction at the connection point (point A) between the end cap 2 and the cylinder 1 after the pressure equipment is deformed by an explosion, and the line connecting the connection point and the point of maximum deflection of the deformed cylinder (point B).

[0046] S3: Determine the damage level of the cylinder of the pressure equipment.

[0047] The value of the cylinder section deflection angle θ calculated in step S2 is compared with the preset damage level criterion to determine the final damage level of the pressure equipment.

[0048] The aforementioned rapid prediction method for damage to the cylinder of metal pressure equipment under external explosion load is based on formula calculation. The calculation process is fast and simple, and there is no need to build and solve complex finite element models of pressure equipment, which greatly improves the prediction efficiency. At the same time, it reduces the professional skills requirements and learning costs for engineers, and lowers the technical threshold.

[0049] It is worth noting that the prediction method in this application is based on the deformation angle of the cylinder of a pressure-bearing device under external explosive loads in the absence of internal pressure, to infer its damage level. This approach fully considers the safety and conservatism principles of engineering applications. Its rationale lies in the fact that, under actual operating conditions, internal pressure increases the overall structural rigidity of the equipment, thereby reducing the cylinder cross-sectional deflection angle θ under the same external explosive load. For conservative reasons, this invention, by calculating the deformation angle of the cylinder under no-internal-pressure conditions, can quickly determine the damage level.

[0050] In some embodiments of this application, the damage level criterion in step S3 is specifically as follows:

[0051] When 0° < θ ≤ 2°, the cylinder is judged to have suffered minor damage (Level I).

[0052] When 2° < θ ≤ 5°, the cylinder is judged to have suffered general damage (Level II).

[0053] When 5° < θ ≤ 10°, the cylinder is judged to have suffered significant damage (Level III).

[0054] When θ > 10°, the cylinder is considered to have suffered severe damage (Level IV).

[0055] In these embodiments, by providing clear damage level classification criteria, objective and non-arbitrary judgment standards are offered, making the prediction results consistent and comparable. This provides a clear and direct basis for subsequent decisions (such as repair, scrapping, etc.).

[0056] In some embodiments of this application, specific physical state descriptions are given for damage levels I and II:

[0057] Level I damage is described as: no macroscopic plastic deformation of the cross section. This indicates that there is almost no plastic deformation of the cross section, meaning that the deformation of the structure remains entirely within the elastic range of the material, and the structure can return to its original state after the load is removed, with its performance and integrity not being substantially affected.

[0058] Level II damage is described as: local yielding occurs, but the overall structural deformation is controllable. This indicates that permanent deformation has occurred in a localized area, but the amount of deformation is still within a controllable range and has not led to overall structural instability.

[0059] These embodiments provide physical support for the definition of damage levels, ensuring that numerical ranges correspond one-to-one with observable engineering phenomena, thereby eliminating ambiguity. Class I and Class II damage define a "controllable damage zone," that is, an area where structural integrity has not been fundamentally compromised, providing a solid basis for assessing the remaining life or repairability of equipment.

[0060] In some embodiments of this application, specific physical state descriptions are given for damage levels III and IV:

[0061] Level III damage is described as significant plastic deformation. This indicates that the permanent deformation of the structure is already quite significant, and the structural integrity has been greatly affected.

[0062] Level IV damage is described as severe plastic deformation sufficient to cause fracture or support failure. This indicates that the structure has entered a highly unstable critical state, with deformation reaching a level that enables it to fracture or support failure, representing an impending or already occurring catastrophic failure.

[0063] Class III and Class IV damage define a "structural failure zone," which is a dangerous area where the structural integrity has been compromised or is on the verge of failure.

[0064] In some embodiments of this application, the method for obtaining the maximum impulse per unit area I can be as follows: First, determine the explosion energy W of the external explosion load (usually expressed as the equivalent mass of TNT explosive, in kilograms (kg)) and the distance R between the explosion source center and the pressure-bearing equipment (in meters (m)). Then, based on these two parameters, calculate the maximum impulse per unit area acting on the surface of the pressure-bearing equipment using well-known empirical formulas or by consulting standardized engineering charts. Of course, the impulse I can also be directly measured in experiments using specialized sensors or simulated using fluid dynamics software; this invention does not impose any particular limitation on this method.

[0065] To better understand this invention, a specific implementation example is given below.

[0066] A single-layer bottle-shaped container may be subjected to external explosive impact during its service life. The method described in this application is used to quickly predict its damage level.

[0067] 1. Determine the explosion load and design parameters of pressure-bearing equipment.

[0068] Explosion load: The potential explosion energy is estimated to be equivalent to W = 5 kg TNT, and the distance from the center of the explosion source to the geometric center of the container is R = 420 mm (0.42 m).

[0069] Based on the explosion energy W and distance R, the maximum impulse per unit area acting on the container surface is calculated to be I = 2.6 × 10³ psi·ms.

[0070] Equipment parameters:

[0071] The length of the container body is L = 1325 mm (1.325 m);

[0072] The outer diameter of the container cylinder is D = 485 mm (0.485 m);

[0073] The container wall thickness δ = 8 mm (0.008 m);

[0074] The material is 4130X;

[0075] Material yield strength σy =598MPa(5.98×10 8 Pa);

[0076] The material density ρ = 7850 kg / m³.

[0077] 2. Calculate the deflection angle θ of the cylinder section.

[0078] Substitute all the above parameters into the prediction formula of this invention:

[0079] ;

[0080] Calculations show that the deflection angle of the cylinder section is approximately 6.4°.

[0081] 3. Determine the degree of damage.

[0082] The calculated result θ=6.4° was compared with the damage level criterion.

[0083] The result satisfies the range of 5° < 6.4° ≤ 10°.

[0084] Therefore, it can be quickly predicted that the pressure vessel cylinder will suffer significant damage (Level III) under a given explosive load. Its physical state is described as exhibiting significant plastic deformation.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load, characterized in that, Includes the following steps: S1: Obtain the parameters of the metal pressure-bearing equipment to be predicted, the parameters including at least: cylinder length L, cylinder outer diameter D, cylinder thickness δ, and material yield strength σ. y And the material density ρ; at the same time, obtain the maximum impulse per unit area I of the external explosion load acting on the pressure-bearing equipment; S2: Based on the parameters obtained in step S1, calculate the deflection angle θ of the cylinder section of the pressure-bearing equipment using the following formula: ； S3: Compare the cylinder section deflection angle θ calculated in S2 with the preset damage level criterion to determine the cylinder damage level of the pressure-bearing equipment.

2. The method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load according to claim 1, characterized in that, The damage level determination criterion in step S3 is as follows: When the calculated deflection angle θ of the cylinder cross section satisfies 0° < θ ≤ 2°, the cylinder is determined to have suffered minor damage. When the calculated deflection angle θ of the cylinder section satisfies 2° < θ ≤ 5°, the cylinder is determined to have suffered general damage. When the calculated deflection angle θ of the cylinder cross section satisfies 5° < θ ≤ 10°, the cylinder is determined to have suffered significant damage. When the calculated deflection angle θ of the cylinder cross section satisfies θ>10°, the cylinder is determined to be severely damaged.

3. The method for rapid prediction of damage to the cylinder of a metal pressure-bearing equipment under external explosion load according to claim 1, characterized in that, The deflection angle θ of the cylinder section is defined as the angle formed by the axial tangent direction at the connection point between the end cap of the pressure equipment and the cylinder, and the line connecting the connection point and the point of maximum cylinder deflection after the explosion deformation.

4. The method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load according to claim 2, characterized in that, When the cylinder is determined to have suffered minor damage, its damage state is described as no substantial plastic deformation of the cross section. When the cylinder is determined to have suffered general damage, its damage state is described as local yielding, and the overall deformation of the structure is controllable.

5. The method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load according to claim 2, characterized in that, When it is determined that the cylinder has suffered significant damage, its damage state is described as having undergone obvious plastic deformation. When the cylinder is determined to be severely damaged, its damage state is described as severe plastic deformation, and the severe plastic deformation is sufficient to cause fracture or support failure.

6. The method for rapid prediction of damage to the cylinder of a metal pressure-bearing device under external explosion load according to any one of claims 1-5, characterized in that, The step of obtaining the maximum impulse per unit area I in step S1 specifically includes: obtaining the explosion energy W of the external explosion load; obtaining the distance R between the explosion source center and the pressure-bearing device; and calculating the maximum impulse per unit area I based on the explosion energy W and the distance R.

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