Deepwater explosion test method based on underwater double-pendulum motion theory

Abstract

The invention discloses a deepwater explosion test method based on an underwater double-pendulum motion theory, and relates to the technical field of ocean engineering.According to the method, a structure that a second mass-free rope is additionally used for hanging a balance weight below a cartridge bag is adopted, then the cartridge bag and the balance weight are regarded as a double-pendulum system, a target is regarded as a system foundation of the double-pendulum system for stress analysis, and a deep-water explosion test result is obtained; the length of the second mass-free rope enabling the swing angle of the cartridge bag to be minimum and the mass of the balance weight are determined, so that the deepwater explosion test method is carried out under the structure, the swing angle of the cartridge bag in the deepwater explosion test process can be effectively reduced, it is guaranteed that the swing angle of the cartridge bag is within an acceptable range, and then effective test data are obtained. And a technical support is provided for improving the deep sea explosion test capability.

Description

Technical Field

[0001] This application relates to the field of marine engineering technology, and in particular to a deep-water explosion test method based on the theory of double pendulum motion in water. Background Technology

[0002] As human exploration of marine resources deepens, deep-water blasting technology is applied in numerous scenarios, including marine resource exploration, marine engineering and port construction, and marine geological research. Due to the influence of high hydrostatic pressure, the pressure load characteristics of deep-water blasting differ significantly from those of shallow-water blasting. Current experimental research on deep-water blasting primarily simulates the deep-water environment within pressure vessels through pressurization. While relatively economical and feasible, this approach is severely limited by the strength requirements of the pressure vessel itself and the presence of reflected waves from the vessel walls, as well as strict constraints on experimental conditions such as the amount of explosive and the simulated water depth.

[0003] Therefore, the best approach to deep-water explosion research is to conduct experimental studies in actual deep-water environments: a target is suspended at a predetermined depth using steel cables, and the explosive charge is suspended at a predetermined distance below the target using nylon ropes. Deep-water explosion tests are then conducted to obtain relevant experimental data and determine the pressure load characteristics of deep-water explosions. Ideally, the explosive charge should be directly below the target; however, the complex marine environment and swells can cause irregular swaying of both the target and the explosive charge, resulting in random variations in the angle of attack of the explosive charge relative to the target, thus affecting the accuracy of the experimental results. Summary of the Invention

[0004] This application addresses the aforementioned problems and technical needs by proposing a deep-water explosion test method based on the theory of double pendulum motion in water. The technical solution of this application is as follows: A deep-water explosion test method based on the theory of double pendulum motion in water, the deep-water explosion test method includes: The structure of the deep-water explosion test system includes: a target deployed in a deep-water environment, through a length of... The first massless rope suspends the medicine bag below the target, and the second massless rope suspends the counterweight below the medicine bag. The drug pack and its weight are considered as a double pendulum system, and the target is considered as the system foundation. Taking into account the periodic driving force of the system foundation by waves, and the buoyancy, drag, and adhering water effects experienced by the double pendulum system during its motion in water, the pendulum angle of the drug pack is determined. The length of the second massless rope and the mass of the counterweight The functional relationship between them is used to determine the swing angle of the medicine pack. The minimum length of the second massless rope and the mass of the counterweight ; Based on the structure of the deep-water explosion test system, the determined length of the second massless rope was adopted. and the mass of the counterweight A deep-water explosion test system was built, and deep-water explosion tests were carried out using the deep-water explosion test system.

[0005] A further technical solution involves constructing the swing angle of the medicine pack. The length of the second massless rope and the mass of the counterweight The functional relationships between them include: The angle of the medicine pack's swing and the swing angle of the counterweight Using these as two generalized coordinates, and considering the system's foundation being driven by the periodicity of waves, and the double pendulum system being subjected to buoyancy, resistance, and the effects of adhering water as it moves in water, we construct the generalized coordinates respectively. and generalized coordinates The Lagrange equations of motion.

[0006] Its further technical solution is to construct a generalized coordinate system. and generalized coordinates The Lagrange equations of motion include: A three-dimensional coordinate system is established with the initial position of the target as the origin. direction and The directions are perpendicular to each other on the horizontal plane. The direction is vertical; the system foundation is determined at any given moment when it is periodically driven by waves, based on the wave parameters of the target test environment of the deep-water explosion test. exist Direction position ,in, It's the waves. Amplitude in direction, It is the wave frequency; Based on the system foundation at any time Location Location of the medicine pack and velocity vector The expression, and the location for constructing the weights. and velocity vector The expression for the double pendulum system at any given time is determined. An expression for the resistance encountered, used to construct a generalized coordinate system. and generalized coordinates The Lagrange equations of motion.

[0007] Its further technical solution is to construct the location of the medicine package. The expression is Velocity vector The expression is To determine the exact moment when the medicine pack moves in the water The expression for the resistance is: ;in, It is the drag coefficient; Location of the counterweight The expression is Velocity vector The expression is Determine the position of the counterweight at any given moment during its movement in the water. The expression for the resistance is: .

[0008] Its further technical solution is to construct a generalized coordinate system. The Lagrange equations of motion include:

[0009] in, It is kinetic energy. It is potential energy. It is a generalized force that is neither conservative nor conservative, and:

[0010]

[0011]

[0012]

[0013] in, It's the quality of the medicine packet. It's the quality of the water attached to the medicine packet. It is the mass of the counterweight. It is the mass of the water attached to the counterweight; It refers to the volume of the medicine packet. It is the volume of the counterweight. It is gravitational acceleration. It refers to the liquid density in deep-water environments. It's a medicine packet. Cross-sectional area on a plane.

[0014] Its further technical solution is to construct a generalized coordinate system. The Lagrange equations of motion include:

[0015] in, It is kinetic energy. It is potential energy. It is a generalized force that is neither conservative nor conservative, and:

[0016]

[0017]

[0018]

[0019] in, It is the mass of the counterweight. It is the mass of the water attached to the counterweight; It is the volume of the counterweight. It is gravitational acceleration. It refers to the liquid density in deep-water environments. It is the diameter of the cylindrical counterweight. It is the length of the cylindrical counterweight. It is a counterweight Cross-sectional area on a plane.

[0020] A further technical solution is to obtain the swing angle of the medicine pack. The minimum length of the second massless rope and the mass of the counterweight include: Using the Lagrange equations of motion to study the double pendulum system in length and quality Motion analysis was performed under different combinations of values ​​to obtain the swing angle. The curve showing the change over time was used to determine the angle at which the medicine pack oscillated. The minimum length of the second massless rope and the mass of the counterweight The possible combinations of values; Among them, the natural frequency of the drug pack during motion analysis is according to The natural frequency of the counterweight is calculated according to... calculate.

[0021] A further technical solution involves a cylindrical explosive charge suspended horizontally below the target via a first massless rope, the radius of which is [missing information]. , length is The quality of the water attached to the medicine packet The medicine packet is in Cross-sectional area on a plane .

[0022] A further technical solution involves a cylindrical counterweight suspended below the medicine pack via a second massless rope, with the counterweight's diameter being [missing information]. , length is The mass of the attached water of the counterweight Counterweight in Cross-sectional area on a plane .

[0023] The beneficial technical effects of this application are: This application discloses a deep-sea explosion test method based on the theory of double pendulum motion in water. The method employs a structure in which a counterweight is suspended below the explosive charge using a second massless rope. The explosive charge and the counterweight are then treated as a double pendulum system, with the target considered as the system foundation for the double pendulum system. Force analysis is performed to determine the length of the second massless rope and the mass of the counterweight that minimize the swing angle of the explosive charge. This method can effectively reduce the swing angle of the explosive charge during deep-sea explosion tests, ensuring that the swing angle is within an acceptable range, thereby obtaining effective test data and providing technical support for improving deep-sea explosion test capabilities. Attached Figure Description

[0024] Figure 1 This is a flowchart of a deep-water explosion test method according to an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of the structure of a deep-water explosion test system in one embodiment of this application.

[0026] Figure 3 In one example, the time curves of the swing angles of the medicine pack and the counterweight are obtained using the method of this application when the mass of the counterweight is 1 kg and the second massless rope is of different lengths.

[0027] Figure 4 In one example, the time curves of the swing angles of the medicine pack and the counterweight are obtained using the method of this application when the mass of the counterweight is 3 kg and the second massless rope is of different lengths.

[0028] Figure 5 In one example, the time curves of the swing angles of the medicine pack and the counterweight are obtained using the method of this application when the mass of the counterweight is 5 kg and the second massless rope is of different lengths.

[0029] Figure 6 In one example, the time curves of the swing angles of the medicine pack and the counterweight are obtained using the method of this application when the mass of the counterweight is 10 kg and the second massless rope is of different lengths. Detailed Implementation

[0030] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0031] This application discloses a deep-water explosion test method based on the theory of double pendulum motion in water, including the following steps, please refer to... Figure 1 The flowchart shown: Step 110: First, determine the structure of the deep-water explosion test system. Please refer to... Figure 2 The structural diagram includes a target 210 deployed in a deep-water scenario, with a length of... The first massless rope 220 is suspended from the medicine pack 230 below the target 210, and the second massless rope 240 is suspended from the counterweight 250 below the medicine pack 230.

[0032] In this system, the specifications of the target 210, the first massless rope 220, and the explosive charge 230 are pre-designed according to the experimental requirements of deep-water blast tests, among which: The specifications of target 210 have little impact on the overall system, and will not be elaborated upon in this application.

[0033] The specifications of the first massless rope 220 include its length. The first massless rope 220 can be made of a lightweight rope such as nylon rope, whose mass can be ignored within the tolerance range.

[0034] The specifications of medicine pack 230 include the shape and weight of the medicine pack. In one embodiment, the explosive charge 230 has a cylindrical structure and is suspended below the target 210 by a first massless rope 220. The radius of the explosive charge 230 is... , length is In standard applications, the drug pack 230 is suspended horizontally below the target 210 with its axis horizontal.

[0035] As an auxiliary structure in deep-water explosion tests, the suspension parameters of counterweight 250 can be adjusted independently. These parameters include the specifications of the second massless rope 240 and the counterweight 250 itself. The specifications of the second massless rope 240 include its length. The second massless rope 240 can also be made of a lightweight rope such as nylon rope, whose mass can be ignored within the error range.

[0036] The specifications of counterweight 250 include its shape and weight. In one embodiment, the counterweight 250 has a cylindrical structure and is suspended below the medicine pack 230 by a second massless rope 240. The diameter of the counterweight 250 is... , length is To reduce the drag of the counterweight 250, the counterweight 250 is suspended vertically below the medicine pack 230.

[0037] Step 120: Treat the drug pack and its accompanying weight as a double pendulum system, and the target as the system basis of the double pendulum system, to construct the swing angle of the drug pack. The length of the second massless rope and the mass of the counterweight The functional relationship between them is used to determine the swing angle of the medicine pack. The minimum length of the second massless rope and the mass of the counterweight .

[0038] Theoretically, suspending a counterweight 250 below the medicine pack can reduce its swaying. However, in reality, the influence of the counterweight 250 on the swaying process is greatly affected by the suspension parameters of the counterweight 250. Among these parameters, the shape of the counterweight 250 has a relatively small impact. Therefore, the shape of the counterweight 250 is usually predetermined and fixed. The length of the second massless rope 240... And the weight of 250 Different values ​​of have a significant impact on the swinging process of the medicine pack 230. If the length is determined solely based on experience... and quality If the value of the counterweight is set too low, then the effect of 250 on optimizing the swing amplitude of the medicine pack is limited, and in some cases it may even increase the swing amplitude of the medicine pack. Therefore, when adopting such a value, Figure 2 Based on the existing structure, step 120 is needed to further determine the suspension parameters of the counterweight 250, especially the appropriate length of the second massless rope 240. And the weight of 250 The value of is determined to ensure that the counterweight of 250 can indeed reduce the swaying of the explosive charge, thereby improving the accuracy of the deep-water explosion test.

[0039] First, a system force analysis is performed on the entire deep-water explosion test system. For ease of description, a three-dimensional coordinate system is established with the initial position of the target's center of gravity as the origin. direction and The directions are perpendicular to each other on the horizontal plane. The direction is downwards along the vertical direction, such as... Figure 2 As shown, the forces acting on the entire deep-water explosion test system include: (1) Target 210 will be affected by waves, causing the system foundation to be affected by waves. The periodic drive in the direction of the deep-water blast test, with pre-determined wave parameters of the target test environment, includes wave parameters in... Amplitude in direction and wave frequency Therefore, it can be determined that when the system foundation is driven by the periodicity of waves at any given time... exist Direction , Indicates time. Therefore, the system foundation at any given time... The position is .

[0040] Corresponding periodic drive speed Periodic driving acceleration is In this application express The first derivative, express The second derivative of is used, and other parameters are expressed similarly. For simplicity, the time parameter is omitted hereafter. .

[0041] Then, based on the system foundation, at any time... Location Location of the medicine pack and velocity vector The expression, and the location for constructing the weights. and velocity vector The expression, specifically: The location of medicine pack 230 can be based on the system's basic location. The swing angle of the medicine pack 230 To describe the swing angle of the medicine pack 230. It is the angle between the first massless rope 220 and the vertical direction. The position of the medicine pack 230. for:

[0042] From this, we can obtain the velocity vector of the medicine pack 230. and speed of movement square The expression is:

[0043]

[0044] The position of the counterweight 250 can be based on the position of the medicine pack 230. And the swing angle of the counterweight 250 To describe the swing angle of the counterweight 250. It is the angle between the second massless rope 240 and the vertical direction. The position of the counterweight 250. for:

[0045] From this, we can obtain the velocity vector of the counterweight 250. and speed of movement square The expression is:

[0046]

[0047] (2) When the medicine pack 230 and the counterweight 250 move in the water, they are subjected to buoyancy. The buoyancy force on the medicine pack 230 is... The buoyancy force on the counterweight 250 is .in, It refers to the liquid density in deep-water environments. It is gravitational acceleration. The medicine packet has a volume of 230. It is the volume of a counterweight of 250.

[0048] In medicine pack 230 and counterweight 250, the following is used: Figure 2 When the cylindrical structure is shown, the volume of the medicine packet 230 is... Volume of counterweight 250 .

[0049] (3) When the medicine pack 230 and the counterweight 250 move in the water, they are also subject to resistance. The resistance experienced by the medicine pack 230 is... The resistance experienced by the counterweight 250 .in, It is the drag coefficient. The speed of the medicine pack's movement is 230. It is the movement speed with a counterweight of 250.

[0050] Based on the constructed velocity vector and velocity vector The expression can be used to obtain the position of the medicine pack at any given moment during its movement in the water. The expression for the resistance is: At any moment when the counterweight moves in the water The expression for the resistance is: .

[0051] (4) When the medicine pack 230 and the counterweight 250 move in the water, the effect of adhering water also needs to be considered. The mass of adhering water of medicine pack 230 is... The mass of the attached water with a counterweight of 250 is .

[0052] The quality of these two attached water tanks is determined based on the structure and suspension method of the chemical pack 230 and the counterweight 250. The chemical pack 230 and the counterweight 250 are designed with the following characteristics in mind: Figure 2 In the case of the cylindrical structure and suspension configuration shown, the mass of attached water of the medicine pack 230 The mass of the attached water with a counterweight of 250 .

[0053] Based on the above force analysis, taking the swing angle of the medicine pack... and the swing angle of the counterweight Using these as two generalized coordinates, and considering that the system's foundation is driven by periodic forces, and that the double pendulum system experiences buoyancy, resistance, and the effects of adhering water as it moves in water, we construct the generalized coordinates respectively. and generalized coordinates The Lagrange equations of motion.

[0054] (a) Constructing generalized coordinates The Lagrange equations of motion are:

[0055] The results were:

[0056] in, It is kinetic energy. It is potential energy. It is a generalized force that is neither conservative nor conservative, and:

[0057]

[0058]

[0059]

[0060] in, It's medicine pack 230. The cross-sectional area on the plane is determined based on the structure and suspension method of the medicine pack 230. The medicine pack 230 employs, for example... Figure 2 With the structure and suspension configuration shown, the medicine pack 230 is in Cross-sectional area on a plane .

[0061] (b) Constructing generalized coordinates The Lagrange equations of motion are:

[0062] The results were:

[0063] in, It is kinetic energy. It is potential energy. It is a generalized force that is neither conservative nor conservative, and:

[0064]

[0065]

[0066]

[0067] in, It is a counterweight of 250. The cross-sectional area on the plane is determined based on the structure and suspension method of the counterweight 250. When the counterweight 250 adopts... Figure 2 With the structure and suspension configuration shown, the counterweight 250 is... Cross-sectional area on a plane .

[0068] Using the Lagrange equations of motion constructed above, the double pendulum system in length and quality By performing motion analysis under different combinations of values, the swing angle can be obtained. The curve showing how the coordinates change over time. In practical applications, a generalized coordinate vector can be defined first. superscript Let's represent the matrix transpose, and then write the above Lagrange equations of motion in matrix form:

[0069] in, Let the mass matrix be:

[0070] Includes all nonlinear terms and ,in:

[0071]

[0072] The natural frequency of the drug pack 230 during motion analysis and the natural frequency of the counterweight 250 Calculate according to the following formula:

[0073]

[0074] According to the swing angle of the medicine pack The length of the second massless rope and the mass of the counterweight By analyzing the time variation curves under different combinations of values, the angle of the medicine pack's swing can ultimately be determined. The minimum length of the second massless rope and the mass of the counterweight The possible combinations of values.

[0075] For example, in one instance, when the mass of the counterweight At that time, the length of the second massless rope The swing angle of the medicine pack when measured at 1 meter, 5 meters, 10 meters, 15 meters, 20 meters, 25 meters, 30 meters, 40 meters, 45 meters, and 50 meters. and the swing angle of the counterweight The curve of change over time is as follows Figure 3 As shown.

[0076] When the mass of the counterweight At that time, the length of the second massless rope The swing angle of the medicine pack when measured at 1 meter, 5 meters, 10 meters, 15 meters, 20 meters, 25 meters, 30 meters, 40 meters, 45 meters, and 50 meters. and the swing angle of the counterweight The curve of change over time is as follows Figure 4 As shown.

[0077] When the mass of the counterweight At that time, the length of the second massless rope The swing angle of the medicine pack when measured at 1 meter, 5 meters, 10 meters, 15 meters, 20 meters, 25 meters, 30 meters, 40 meters, 45 meters, and 50 meters. and the swing angle of the counterweight The curve of change over time is as follows Figure 5 As shown.

[0078] When the mass of the counterweight At that time, the length of the second massless rope The swing angle of the medicine pack when measured at 1 meter, 5 meters, 10 meters, 15 meters, 20 meters, 25 meters, 30 meters, 40 meters, 45 meters, and 50 meters. and the swing angle of the counterweight The curve of change over time is as follows Figure 6 As shown.

[0079] In this example, the final determination of the swing angle of the medicine packet is then made. Minimum counterweight mass The length of the second massless rope In this case, the swing angle of the medicine pack Minimum is .

[0080] Step 130: Based on the structure of the deep-water explosion test system, determine the swing angle of the explosive charge obtained in step 120. The minimum length of the second massless rope and the mass of the counterweight A deep-water explosion test system was built, and deep-water explosion tests were carried out using the deep-water explosion test system.

[0081] The above are merely preferred embodiments of this application, and this application is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of this application should be considered to be included within the protection scope of this application.

Claims

1. A deep-water explosion test method based on the theory of double pendulum motion in water, characterized in that, Deep-water explosion testing methods include: The structure of the deep-water explosion test system includes: a target deployed in a deep-water environment, through a length of... The first massless rope suspends the medicine bag below the target, and the second massless rope suspends the counterweight below the medicine bag. The drug pack and its weight are considered as a double pendulum system, and the target is considered as the system foundation. Taking into account the periodic driving force of the system foundation by waves, and the buoyancy, drag, and adhering water effects experienced by the double pendulum system during its motion in water, the pendulum angle of the drug pack is determined. The length of the second massless rope and the mass of the counterweight The functional relationship between them is used to determine the swing angle of the medicine pack. The minimum length of the second massless rope and the mass of the counterweight ; Based on the structure of the deep-water explosion test system, the determined length of the second massless rope was adopted. and the mass of the counterweight A deep-water explosion test system was built, and deep-water explosion tests were carried out using the deep-water explosion test system.

2. The deep-water explosion test method according to claim 1, characterized in that, The swing angle of the medicine pack The length of the second massless rope and the mass of the counterweight The functional relationships between them include: The angle of the medicine pack's swing and the swing angle of the counterweight Using these as two generalized coordinates, and considering the system's foundation being driven by the periodicity of waves, and the double pendulum system being subjected to buoyancy, resistance, and the effects of adhering water as it moves in water, we construct the generalized coordinates respectively. and generalized coordinates The Lagrange equations of motion.

3. The deep-water explosion test method according to claim 2, characterized in that, Constructing generalized coordinates and generalized coordinates The Lagrange equations of motion include: A three-dimensional coordinate system is established with the initial position of the target as the origin. direction and The directions are perpendicular to each other on the horizontal plane. The direction is vertical; the system foundation is determined at any given moment when it is periodically driven by waves, based on the wave parameters of the target test environment of the deep-water explosion test. exist Direction position ,in, It's the waves. Amplitude in direction, It is the wave frequency; Based on the system foundation at any time Location Location of the medicine pack and velocity vector The expression, and the location for constructing the weights. and velocity vector The expression for the double pendulum system at any given time is determined. An expression for the resistance encountered, used to construct a generalized coordinate system. and generalized coordinates The Lagrange equations of motion.

4. The deep-water explosion test method according to claim 3, characterized in that, Location of the medicine pack The expression is Velocity vector The expression is To determine the exact moment when the medicine pack moves in the water The expression for the resistance is: ;in, It is the drag coefficient; Location of the counterweight The expression is Velocity vector The expression is Determine the position of the counterweight at any given moment during its movement in the water. The expression for the resistance is: .

5. The deep-water explosion test method according to claim 4, characterized in that, Constructing generalized coordinates The Lagrange equations of motion include: in, It is kinetic energy. It is potential energy. It is a generalized force that is neither conservative nor conservative, and: in, It's the quality of the medicine packet. It's the quality of the water attached to the medicine packet. It is the mass of the counterweight. It is the mass of the water attached to the counterweight; It refers to the volume of the medicine packet. It is the volume of the counterweight. It is gravitational acceleration. It refers to the liquid density in deep-water environments. It's a medicine packet. Cross-sectional area on a plane.

6. The deep-water explosion test method according to claim 4, characterized in that, Constructing generalized coordinates The Lagrange equations of motion include: in, It is kinetic energy. It is potential energy. It is a generalized force that is neither conservative nor conservative, and: in, It is the mass of the counterweight. It is the mass of the water attached to the counterweight; It is the volume of the counterweight. It is gravitational acceleration. It refers to the liquid density in deep-water environments. It is the diameter of the cylindrical counterweight. It is the length of the cylindrical counterweight. It is a counterweight Cross-sectional area on a plane.

7. The deep-water explosion test method according to claim 2, characterized in that, The angle at which the medicine packet swings is obtained The minimum length of the second massless rope and the mass of the counterweight include: Using the Lagrange equations of motion to study the double pendulum system in length and quality Motion analysis was performed under different combinations of values ​​to obtain the swing angle. The curve showing the change over time was used to determine the angle at which the medicine packet oscillated. The minimum length of the second massless rope and the mass of the counterweight The possible combinations of values; Among them, the natural frequency of the drug pack during motion analysis is according to The natural frequency of the counterweight is calculated according to... calculate.

8. The deep-water explosion test method according to claim 5 or 7, characterized in that, The explosive charge has a cylindrical structure and is suspended horizontally from the target by a first massless rope. The radius of the explosive charge is [missing information]. , length is The quality of the water attached to the medicine packet The medicine packet is in Cross-sectional area on a plane .

9. The deep-water explosion test method according to any one of claims 5-7, characterized in that, The counterweight is a cylindrical structure and is suspended below the medicine bag by a second massless rope with its axis perpendicular to the horizontal. The diameter of the counterweight is... , length is The mass of the attached water of the counterweight Counterweight in Cross-sectional area on a plane .

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