System for testing spatial distribution state of upward-floating icebreaking load of underwater vehicle

Abstract

The invention relates to a system for testing the spatial distribution state of upward-floating icebreaking loads of an underwater vehicle, and belongs to the technical field of ice pool model tests. Comprising a vertical limb, a horizontal limb, a rigid base and a force transducer, the lower end of the vertical limb is in bolted connection with one end of the horizontal limb, the other end of the horizontal limb is connected with the lower side of the middle of the rigid base, and the rigid base is connected with a model through the force transducer. The device is suitable for various ice pool jacking experiment tests for simulating the upward-floating icebreaking process of the underwater vehicle, the constraint rigidity of each model segment is guaranteed, and synchronous measurement of the upward-floating icebreaking total load and load distribution of the underwater vehicle structure can be achieved; and targeted adaptive design is carried out on different ice water pool environments, so that the sensor array can carry out dynamic measurement under low-temperature water for a long time, and the cost increase caused by overhigh selection standard is also avoided.

Description

Technical Field

[0001] The present invention relates to a test system, belonging to the technical field of ice tank model tests. Background Art

[0002] With the global warming, the polar ocean ice sheet is gradually melting, which promotes the increasing activities of scientific research, commerce and development in the polar sea areas. When an underwater vehicle operates in the polar sea areas, it may face the operation scenario of surfacing through ice. Different from the ice-breaking process of conventional polar navigation ships, the ice-breaking process of an underwater vehicle surfacing through ice involves the fracture and damage of the ice sheet under the action of vertical loads. In this process, the spatial distribution state of the ice load on the underwater vehicle will play a key role in the structural strength design and control design. However, the ice-breaking process of an underwater vehicle surfacing through ice involves a variable multi-physical field coupling process and is closely related to the complex physical and mechanical properties of sea ice materials, resulting in the lack of in-depth and effective research and test methods for this problem in the domestic and international academic and engineering communities.

[0003] Nevertheless, some scholars at home and abroad have made some beneficial attempts on the ice load problem in the ice-breaking process of an underwater vehicle surfacing through ice. With the wide application of the finite element method, discrete element method, smoothed particle method and peridynamics method in the field of ice mechanics, some scholars at home and abroad have used numerical simulation methods to conduct exploratory research on this problem. Among them, Ye et al. (2018) simulated the ice-breaking process of an underwater vehicle surfacing through ice using an aerodynamic mathematical model and analyzed the time-series variation of the structural ice load. Wang et al. (2021) simulated the vertical ice-breaking and surfacing process of an underwater vehicle using LS-DYNA software and considered the nonlinear interaction between the structure, ice and water in the simulation. Yue et al. (2021) determined the main control parameters affecting the dynamic ice load of the structure through dimensional analysis first and then set different initial velocities when simulating the ice-breaking process of the structure surfacing through ice, so as to study the dynamic characteristics of the ice load in the ice-breaking process of the structure surfacing through ice. Ye Liyu et al. (2018) simulated the contact process between the underwater vehicle structure and ice and the failure of the ice sheet using the peridynamics method. In the simulation, the structure was regarded as a rigid body, and the contact positions between the structure and ice were identified through a contact detection algorithm, so as to track the ice-breaking state and the ice load distribution on the structure at each moment. Liu Junjie et al. (2015) simplified the ice-breaking process of an underwater vehicle surfacing through ice into a process in which the structure was impacted by multiple objects and simulated the interference and coupling process between multiple impact forces.

[0004] In addition to the above numerical simulation studies, some domestic and foreign scholars have also carried out some model tests on the collision between ice and typical local structures. Lee et al. (2014) arranged a series of strain force measurement points inside the typical local outer plate of the hull, and tested the deformation of the local outer plate structure of the hull under the action of the loading mechanism. Gagnon (2004) prepared multiple model ice blocks to simulate floating ice blocks, and successively placed these floating ice blocks into the water tank to collide with the ship model, and tested the time history of the contact pressure on the surface of the ship model. Choi et al. (2012) simulated the process of a steel plate structure hitting ice in the laboratory. In the experiment, the inclination angle and impact speed of the steel plate structure were controllable, so as to test the impact force and ice block damage under different inclination angles and speeds. Kim et al. (2014) fixed the grillage structure, released ice blocks at a certain height above the grillage structure, and the ice blocks freely fell to collide with the grillage structure, tested the deformation and fracture of the ice blocks during the collision process, as well as the deformation of the structure, and described the spatial distribution of the ice load on the structure.

[0005] To sum up, the research work on the spatial distribution state of ice load during the upward icebreaking process of an underwater vehicle mainly includes numerical simulation research and local structure model test research. Among them, the numerical simulation research is based on methods such as the finite element method, discrete element method, smoothed particle method, and peridynamics method, and simulates the process of the underwater vehicle model rising and contacting and even breaking the ice cover model. During this process, the ice load acting on the surface of the structure model is calculated. However, due to the complexity of the ice material, it is still impossible to construct a constitutive relationship that can accurately describe the deformation and failure process of the ice cover, resulting in the ice load distribution results obtained by the numerical simulation method still needing to be verified by physical model tests or field tests. On the other hand, the limited physical model test work is mostly aimed at typical local structure models, simulating the collision process between the local structure and ice blocks, so as to observe the ice block failure process and the force condition of the local structure. Limited by the characteristics of the structure test and laboratory conditions, at a large geometric scale ratio, only typical local structures can be tested, and it is impossible to simulate the upward icebreaking process of a complete underwater vehicle model. Moreover, during the upward icebreaking process of the underwater vehicle, there are obviously associated effects of the icebreaking process between various parts of the structure, resulting in certain deviations between the ice load and structure response results measured only focusing on the local structure and the upward icebreaking process of the complete structure.

[0006] Therefore, the existing test systems for the spatial distribution of loads during the upward icebreaking process of underwater vehicles mainly have the following problems:

[0007] 1. It is not adaptively designed for the ice tank test environment. The upward icebreaking process of an underwater vehicle is a complex physical process of structure-ice-water coupling. Only by simulating the upward icebreaking of the vehicle in the ice tank environment can the real action scenario be reproduced. There is no test system suitable for this special test environment, nor is there a targeted design scheme.

[0008] 2. There is no design scheme for synchronously measuring the total ice-breaking load and the load distribution of an underwater vehicle. Existing model test systems all measure the ice-breaking load distribution for a large-scale local model or measure the total ice-breaking load for a small-scale overall model. Obviously, the total ice-breaking load measured by the overall model cannot reflect the load distribution; and the ice-breaking process of an underwater vehicle floating upward is a continuous process, and the ice-breaking processes of various parts of the vehicle structure affect each other. There will be differences between the ice-breaking load measured separately for the local model and the actual ice-breaking process of the overall structure. There is no test system that can simultaneously measure the total ice-breaking load and the load distribution for the overall model of an underwater vehicle.

[0009] Therefore, there is an urgent need to propose a test system for the spatial distribution state of the ice-breaking load of an underwater vehicle floating upward to solve the above technical problems. Summary of the Invention

[0010] To solve the above problems, a test system for the spatial distribution state of the ice-breaking load of an underwater vehicle floating upward is provided. A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0011] Technical solution of the present invention:

[0012] A test system for the spatial distribution state of the ice-breaking load of an underwater vehicle floating upward includes a vertical limb, a horizontal limb, a rigid base, and a force-measuring sensor. The lower end of the vertical limb is bolted to one end of the horizontal limb, and the other end of the horizontal limb is connected to the lower side of the middle part of the rigid base. The model is connected to the rigid base through the force-measuring sensor on the rigid base.

[0013] Preferably: It further includes a connecting plate, and the connecting plate is fixedly connected to the side surface of the upper end of the vertical limb. The connecting plate is used for bolted connection with the moving base of the lifting device.

[0014] Preferably: The angle β between the vertical plane of the vertical limb and the horizontal limb is 90°.

[0015] Preferably: The angle α between the horizontal plane of the model and the horizontal limb is 20° - 70°.

[0016] Preferably: The length of the horizontal limb is greater than or equal to 1 times the characteristic length.

[0017] Preferably: The model includes several sequentially arranged model segments, there is a gap between adjacent model segments, and each model segment is connected to the rigid base through several force-measuring sensors.

[0018] Preferably: in the direction of the model length, when the segmented length of the model is less than or equal to 3 times the length of the force measuring sensor, 1 force measuring sensor is arranged at the middle position of the model segment; when the segmented length of the model is greater than 3 times the length of the force measuring sensor and less than or equal to 6 times, 1 force measuring sensor can be arranged at each of the positions 1 times the length of the force measuring sensor away from the edges at the front and back of the model segment; when the segmented length of the model is greater than 6 times the length of the force measuring sensor, the model segment is further subdivided according to the range of less than 3 times the length or 3 to 6 times the length.

[0019] In the direction of the model width, when the contact width at the bottom of the model is less than or equal to 4 times the width of the force measuring sensor, 1 sensor can be arranged in the width direction of the model; when the contact width at the bottom of the model is greater than 4 times the width of the force measuring sensor and less than or equal to 8 times, 1 force measuring sensor can be arranged at each of the positions 1.5 times the width away from the contact edges on the left and right of the model segment.

[0020] Preferably: when selecting the range of the force measuring sensor, it is necessary to estimate the ice-breaking load of each model segment, and a semi-theoretical and semi-empirical estimation method for the vertical destructive force of the ice layer in the surface contact ice-breaking mode can be used:

[0021]

[0022] In the formula, P f is the vertical failure load of the ice layer when the circumferential crack penetrates; σ N is the flexural strength of the ice layer; h is the ice layer thickness; k is a dimensionless constant; R is the ice layer failure radius, L is the characteristic length of the ice layer, and can be calculated by the following formula:

[0023]

[0024] In the formula, E is the elastic modulus of ice; υ is the Poisson's ratio of ice; ρ w is the density of water.

[0025] Preferably: through holes are provided on the horizontal limb to reduce resistance.

[0026] The present invention has the following beneficial effects:

[0027] 1. The present invention is applicable to the ice pool jacking experiment tests of various types of simulated underwater submersibles during the ice-breaking process of floating up. According to the segmented model design of the underwater submersible, the arrangement method of the force measuring sensor array is designed to ensure the constraint stiffness of each model segment, and can realize the synchronous measurement of the total ice-breaking load and the load distribution of the underwater submersible structure (model) during floating up and ice-breaking.

[0028] 2. The present invention conducts targeted adaptive designs for different ice tank environments, designs the sensor range according to the extreme value estimation results of the upward ice-breaking load of each model segment, and provides a reference standard for selecting force-measuring sensors with low-temperature resistance, anti-interference, and waterproof properties, avoiding inaccurate test results and damage caused by too small a selection, ensuring that the sensor array can perform dynamic measurements underwater at low temperatures for a long time, and also avoiding increased costs caused by too high a selection standard. Brief Description of the Drawings

[0029] Figure 1 is a three-dimensional view of a test system for the spatial distribution state of the upward ice-breaking load of an underwater vehicle.

[0030] Figure 2 is a side view of a test system for the spatial distribution state of the upward ice-breaking load of an underwater vehicle.

[0031] Figure 3 is a top view of a test system for the spatial distribution state of the upward ice-breaking load of an underwater vehicle.

[0032] In the figure, 1 - connecting plate, 2 - vertical limb, 3 - horizontal limb, 4 - rigid base, 5 - force-measuring sensor, 6 - model, 7 - hinge seat, 8 - cushion block, 12 - auxiliary frame. Detailed Embodiments

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be described below through specific embodiments shown in the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0034] Detailed Embodiment 1: In combination with Figures 1-3 This embodiment is described. A test system for the spatial distribution state of the upward ice-breaking load of an underwater vehicle in this embodiment includes a vertical limb 2, a horizontal limb 3, a rigid base 4, and a force-measuring sensor 5. The lower end of the vertical limb 2 is bolted to one end of the horizontal limb 3, and the other end of the horizontal limb 3 is connected to the lower side of the middle of the rigid base 4. The rigid base 4 is connected to the model 6 through the force-measuring sensor 5. The present invention has conducted targeted adaptive designs considering various ice tank environments and is applicable to different ice tank test environments. The force-measuring sensor 5 and its signal line for connecting to the data acquisition system are selected according to waterproof performance, anti-interference performance, and low-temperature performance. The data acquisition system sets functions such as sampling frequency.

[0035] It further includes a connecting plate 1 which is fixedly connected to the upper side of the vertical limb 2 and is used for bolt connection with the moving base of the lifting device; a test system for the spatial distribution state of the upward floating ice-breaking load of an underwater vehicle proposed by the present invention is often used in cooperation with an ice pool simulation test device that can simulate the upward floating ice-breaking process of an underwater vehicle and is installed on such a jacking device to realize the measurement of the ice load on the structure of the target vehicle. For example, the upper end of the support frame of the jacking device is connected to the motor. The support frame has a vertical slideway. A moving base is slidably arranged in the slideway of the support frame. A vertical threaded through hole is machined on the moving base. A transmission lead screw arranged along the slideway is threadedly connected to the moving base through the threaded hole of the moving base. The upper end of the transmission lead screw is connected to the output end of the servo motor through a gearbox, and the gearbox can be fixed to the upper end of the support frame; the present invention has a greater jacking capacity, can support a larger-sized structural model, meets the requirements of a larger scale model test, and thus more realistically simulates the ice-breaking process and mechanical behavior of an underwater vehicle; the present invention is applicable to various types of ice pool jacking devices that simulate the upward floating ice-breaking process of an underwater vehicle, designs the layout method of the force measuring sensor array according to the segmented model of the underwater vehicle and the type of the jacking device, ensures the constraint stiffness of each model segment, and can realize the synchronous measurement of the total upward floating ice-breaking load and the load distribution of the underwater vehicle structure;

[0036] The vertical angle β between the vertical limb 2 and the horizontal limb 3 is 90°, which is mainly used to extend the submersible structure model to a certain distance under the ice, avoiding the damage to the ice cover by the jacking device during the test, and at the same time ensuring that the submersible model has sufficient circumferential and vertical floating spaces; it also includes an auxiliary frame 12, and the auxiliary frame 12 is arranged on the side of the other end of the horizontal limb 3 through bolts, and the auxiliary frame 12 is connected to the attitude adjustment module; the auxiliary frame 12 includes two triangular frames, which are arranged on both sides of the horizontal limb 3 and the plane formed by the triangular frames is parallel to the horizontal plane. Both the vertical limb 2 and the horizontal limb 3 are straight steel frames; the present invention has the integrity of crack propagation. Through the design of the support module, it ensures a reasonable distance between the model and the ice cover, so that the model will not affect the integrity of the ice cover during the ice-breaking process, and can truly capture the formation and propagation behavior of ice-breaking cracks; it also includes a hinge seat 7 and two pads 8. The horizontal limb 3 is rotatably connected to the force measurement module through the hinge seat 7, that is, the other end of the horizontal limb 3 is fixedly connected to the rotating shaft of the hinge seat 7, and the rigid base 4 is fixedly connected to the bearing seat of the hinge seat 7. The rotating shaft and the inner ring of the bearing seat are interference-fitted to achieve rotational connection. The horizontal limb 3 is fixedly connected to the rigid base 4 through two pads 8; the present invention has the adaptability to multi-scene tests. By flexibly controlling the tilt angle of the model through the hinge seat and fixed pads, the structure model is constrained at different inclination angles to meet the requirements of various test scenarios; the force measurement sensor 5 is used to record in real time the load received during the floating ice-breaking process of the model; the force measurement sensor 5 is arranged on the upper part of the rigid base 4. The lower part of the rigid base 4 is bolted to the bearing seat of the hinge seat 7 and the pads 8. The two pads 8 are located on both sides of the hinge seat 7. The pads 8 are bolted to the auxiliary frame 12. A number of bolt holes can be arranged at the lower part of the rigid base 4, and the auxiliary frame 12 can be connected to bolt holes at different positions as needed, so as to adjust the force arm;

[0037] The horizontal plane angle α between the model 6 and the horizontal limb 3 is 20° - 70°; in order to ensure that the two ends of the model are as far away from the pool wall of the ice pool as possible and avoid the influence of boundary effects, it can be adjusted according to the actual ice pool environment of the application. The rigid base 4 is a steel structure beam;

[0038] The length of the horizontal limb 3 is greater than or equal to 1 times the characteristic length; the length of the radial crack can be measured by the characteristic length shown in formula (2). When the distance between the model boundary and the free edge of the ice cover exceeds 1 times the characteristic length, the influence of boundary effects can be ignored; it meets the requirements of lifting force, speed range and accuracy, lifting stroke, and structural strength and stiffness in the floating ice-breaking test, etc. At the same time, the boundary effects (free end edge and pool wall boundary) of the model ice cover will not interfere with the floating ice-breaking process of the submersible model;

[0039] The model 6 is a segmented model. The model 6 includes a number of sequentially arranged model segments, with gaps between adjacent model segments. Each model segment is connected to the rigid base 4 through a number of force measuring sensors 5. The present invention has efficient data acquisition capabilities, and the equipped high-precision force measuring sensors can record and analyze the ice load conditions during the icebreaking process in real time. It supports segmented or integral models. Through the flexible configuration of sensors, it can accurately measure the total load or load distribution during the icebreaking process, providing reliable data for structural mechanics research. The present invention can synchronously measure the total load and load distribution of the complete underwater vehicle model floating up and breaking ice. On the premise of truly reproducing the process of the complete underwater vehicle floating up and breaking ice, a synchronous measurement system for the total icebreaking load and the spatial load distribution state is constructed, which can be applied to various underwater vehicle structures.

[0040] In the length direction of the model 6, when the length of the model segment is less than or equal to 3 times the length of the force measuring sensor 5, 1 force measuring sensor 5 is arranged at the middle position of the model segment. When the length of the model segment is greater than 3 times the length of the force measuring sensor and less than or equal to 6 times, 1 force measuring sensor can be arranged at a distance of 1 times the length of the force measuring sensor 5 from the edge at the front and back of the model segment. When the length of the model segment is greater than 6 times the length of the force measuring sensor, the model segment is further subdivided according to the range of less than 3 times the length or 3 times to 6 times the length.

[0041] In the width direction of the model 6, when the bottom contact width of the model 6 is less than or equal to 4 times the width of the force measuring sensor 5, 1 sensor can be arranged in the width direction of the model. When the bottom contact width of the model is greater than 4 times the width of the force measuring sensor 5 and less than or equal to 8 times, 1 force measuring sensor 5 can be arranged at a distance of 1.5 times the width from the contact edge on the left and right of the model segment. The arrangement of the force measuring sensors 5 in the two directions forms an arrangement array of sensors.

[0042] When selecting the range of the force measuring sensor, it is necessary to estimate the icebreaking load of each model segment. The semi-theoretical and semi-empirical estimation method for the vertical destructive force of the ice layer in the surface contact icebreaking mode can be used:

[0043]

[0044] In the formula, P f is the vertical failure load of the ice layer when the circumferential crack penetrates; σ N is the flexural strength of the ice layer; h is the ice layer thickness; k is a dimensionless constant; R is the ice layer failure radius, and L is the characteristic length of the ice layer, which can be calculated by the following formula:

[0045]

[0046] In the formula, E is the elastic modulus of the ice; υ is the Poisson's ratio of the ice; ρ w is the density of water;

[0047] The measuring range of the force sensor (5) is 500 kgf, the sensor accuracy is 0.05% F.S., the dust and waterproof level is IP68, and the operating temperature range is -20°C to 80°C; the present invention has carried out targeted adaptability design for different ice pool environments, designed the sensor measuring range according to the estimated extreme values of the floating ice-breaking load for each model segment, and selected a force sensor model with low-temperature resistance, anti-interference and waterproof performance to ensure that the sensor array can perform dynamic measurements in low-temperature underwater for a long time;

[0048] A through hole 31 is provided on the horizontal limb 3 to reduce resistance.

[0049] Embodiment 1:

[0050] Taking a test system for the spatial distribution state of the floating ice-breaking load of an underwater vehicle and a type-I ice pool underwater vehicle lifting device as an example, the connection and installation of the test system are described as follows:

[0051] (1) Lifting device:

[0052] A type-I lifting device suitable for simulating the floating ice-breaking process of an underwater vehicle in an ice pool is the installation basis of a test system for the spatial distribution state of the floating ice-breaking load of an underwater vehicle proposed by the present invention. The test system needs to be designed and modified according to the lifting device and the underwater vehicle model and installed on the lifting device to effectively measure the spatial distribution of the structural ice-breaking load; the lifting device generally includes a lifting device, an overhanging device and a rigid base, which can effectively control the floating speed and floating angle of the underwater vehicle model; among them, the lifting device is generally installed on a test trailer that spans the width direction of the ice pool and can move along the length direction of the pool, and the vertical movement of the lifting device is driven and controlled by a servo system to ensure that the lifting device has sufficient lifting force, motion control accuracy and stroke range; the overhanging device generally consists of a vertical limb member and a horizontal limb member. Among them, the vertical limb member is used to submerge the underwater vehicle model downward to a certain depth underwater to ensure that the structural model has sufficient floating motion space; the horizontal limb member is used to extend the underwater vehicle model forward into the ice for a certain distance to avoid the interference of the ice cover edge on the floating ice-breaking process; the rigid base is the main component for carrying the underwater vehicle model, and the main dimensions need to meet the installation requirements of the structural model and have sufficient stiffness to avoid deformation and vibration during the vertical movement; at the same time, the rigid base should have the function of adjusting the inclination angle to simulate the floating ice-breaking scenarios of the underwater vehicle at different inclination angles;

[0053] (2) Segmented model:

[0054] The length of the currently commonly used underwater vehicle structure (Model 6) is greater than its width and height, and this feature is more obvious in large underwater vehicle structures. According to the structural characteristics, in order to effectively measure the spatial distribution of ice loads on the underwater vehicle model, the structural model can be designed as a segmented type along the length direction. The specific principles and methods for segmentation are as follows:

[0055] ① The position where the underwater vehicle first touches the ice when floating is the initial concentrated area of ice loads. The range that completely contains this ice-touching area should be divided into one segment. In addition, the front and rear positions of this segment also need to refer to the hull form along the length direction to ensure the continuity of the hull form between segments;

[0056] ② The protruding parts in the hull form of the underwater vehicle structure should be divided into one segment to reflect the corresponding relationship between the hull form characteristics and the ice load distribution;

[0057] ③ On the basis of the above two principles, the remaining non-segmented parts of the underwater vehicle are divided according to the principle that the segment lengths are as uniform as possible;

[0058] ④ To avoid the mutual influence of ice loads between segments and at the same time maintain the overall shape of the underwater vehicle structure, an appropriate gap should be left between segments, which neither changes the hull form nor causes the segments to contact each other during the floating and ice-breaking process;

[0059] (3) Arrangement of force-measuring sensors:

[0060] The force-measuring sensor array in the test system of the present invention is arranged between the rigid base and the segmented model, and is fixed to the rigid base and the model segments respectively by bolts, playing the role of connecting the two components and measuring the ice loads. The number, position and arrangement method of the force-measuring sensors need to be determined according to the size and shape of the structural model segments. The specific principles and methods for arrangement are as follows:

[0061] ① The principle of arranging the force-measuring sensors is to ensure that each model segment has sufficient connection strength and stiffness to prevent the model segment from displacing during the floating and ice-breaking process due to unstable fixed bases. One to two independent force-measuring sensors are arranged under each model segment, determined according to the length of the model segment;

[0062] ② Along the length direction of the model segment, when the length of the model segment is less than or equal to 3 times the length of the force-measuring sensor, one force-measuring sensor can be arranged at the middle position of the model segment; when the length of the model segment is greater than 3 times and less than or equal to 6 times the length of the force-measuring sensor, one force-measuring sensor can be arranged at each position 1 times the sensor length away from the edge at the front and rear of the model segment; when the length of the model is greater than 6 times the length of the force-measuring sensor, the model segment is further subdivided;

[0063] ③ In the direction along the width of the model segment, since most underwater vehicles have a cylindrical structure, the width of the bottom of the structure will be smaller than the model width. When the contact width at the bottom of the model is less than or equal to 4 times the width of the force-measuring sensor, 1 sensor can be arranged in the width direction of the model. When the contact width at the bottom of the model is greater than 4 times the width of the force-measuring sensor and less than or equal to 8 times, 1 force-measuring sensor can be arranged at a position 1.5 times the width from the contact edge on the left and right of the model segment. According to the length-width ratio of the underwater vehicle configuration, generally, the width of the model segment will not be greater than 8 times the width of the force-measuring sensor. If such a special configuration occurs, it is recommended to divide the model into two half-regions (segments) along the width direction as well. The present invention arranges sensors according to the segments, and further improves the segments considering the sensor arrangement, establishing a stable test system; avoiding inaccurate test results and damage caused by too small a selection, ensuring that the sensor array can perform dynamic measurements in low-temperature water for a long time, and also avoiding an increase in cost caused by too high a selection criterion;

[0064] (4) Selection of force-measuring sensors:

[0065] When selecting the range of the force-measuring sensor, first, it is necessary to estimate the ice-breaking load of each model segment. The semi-theoretical and semi-empirical estimation method of the vertical destructive force of the ice layer in the surface contact ice-breaking mode proposed by Kerr can be used:

[0066]

[0067] In the formula, P f is the vertical failure load of the ice layer when the circumferential crack penetrates; σ N is the flexural strength of the ice layer; h is the ice layer thickness; k is a dimensionless constant; R is the ice layer failure radius; L is the characteristic length of the ice layer, which can be calculated by the following formula:

[0068]

[0069] In the formula, E is the elastic modulus of the ice; υ is the Poisson's ratio of the ice; ρ w is the density of water;

[0070] When estimating the extreme value of the upward ice-breaking load of the model segment, the mutual influence between each segment can be temporarily not considered, and the ice-breaking load is calculated separately for each model segment according to its structural type, and the range of the sensor is designed in combination with the number of force-measuring sensors below the segment. On the other hand, the force-measuring sensor array needs to work underwater, and the sensor should have good low-temperature resistance, anti-interference and waterproof performance, and have the ability of dynamic testing, and the test frequency is not less than 100Hz.

[0071] In this embodiment, the length of the underwater vehicle model in the test is about 4.5 m. According to the structural line shape of the underwater vehicle, it is evenly divided into 10 segments along the length direction, and the length of each segment is about 45 cm. The length of the force measuring sensor 5 to be selected is 15 cm, so one force measuring sensor 5 is arranged at the middle position of each model segment 6 along the length direction. The underwater vehicle model is in a cylindrical configuration, and the bottom surface is arc-shaped. The width of the force measuring sensor 5 is 5 cm, so one force measuring sensor 5 is arranged at the middle position of each model segment 6 along the width direction. In summary, arranging one force measuring sensor 5 at the middle position of each model segment 6 can meet the connection stiffness requirements of the model segments. At the same time, a 1-cm gap is left between each model segment 6 to avoid the mutual influence of ice loads between segments.

[0072] Estimate the upward ice-breaking load of the underwater vehicle model according to the Kerr formula. The length of the underwater vehicle model is about 5 m, evenly divided into 10 segments along the length direction. The ice thickness of the model for the planned test is 10 cm, so the estimated ice-breaking load of the largest segment is about 150 kgf. Considering the dynamic amplification of the vertical load during the test, the range of the selected force measuring sensor 5 is 500 kgf, the sensor accuracy is 0.05% F.S., the dust and waterproof grade is IP68, and the working temperature range is -20°C to 80°C. Thus, the synchronous measurement of the total upward ice-breaking load and the load spatial distribution of the target underwater vehicle model is realized through the force measuring sensor array.

[0073] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined. Those skilled in the art can exhaust all possibilities according to the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0074] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load, characterized by: The invention comprises a vertical limb (2), a horizontal limb (3), a rigid base (4) and a force sensor (5), wherein the lower end of the vertical limb (2) is connected to one end of the horizontal limb (3), the other end of the horizontal limb (3) is connected to the rigid base (4), and the rigid base (4) is connected to a model (6) via the force sensor (5).

2. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 1, characterized in that: It also comprises a connecting plate (1), which is connected to the upper end side of the standing limb (2), and the connecting plate (1) is used to be connected to the lifting device by bolts.

3. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 1, characterized in that: The angle β between the vertical limb (2) and the horizontal limb (3) is 90°.

4. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 1 or 3, characterized in that: The horizontal plane angle between the model (6) and the horizontal limb (3) is α=20°-70°.

5. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 4, characterized in that: The length of the horizontal limb (3) is greater than or equal to 1 times the characteristic length.

6. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 1, characterized in that: The model (6) comprises a plurality of model segments arranged in sequence, with gaps between adjacent model segments, and each model segment is connected to a rigid base (4) via a plurality of force sensors (5).

7. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 6, characterized in that: In the length direction of the model (6), when the length of the model segment is less than or equal to 3 times the length of the force sensor (5), one force sensor (5) is arranged in the middle of the model segment; when the length of the model segment is greater than 3 times and less than or equal to 6 times the length of the force sensor, one force sensor can be arranged at the front and rear of the model segment at a distance of 1 times the length of the force sensor (5) from the edge; when the length of the model segment is greater than 6 times the length of the force sensor, the model segment is further subdivided according to a range of less than 3 times the length or 3 to 6 times the length; Along the width direction of the model (6), when the contact width of the bottom of the model (6) is less than or equal to 4 times the width of the force sensor (5), one sensor can be arranged in the width direction of the model; when the contact width of the bottom of the model is greater than 4 times and less than or equal to 8 times the width of the force sensor (5), one force sensor (5) can be arranged at each of the left and right sides of the model segment at a distance of 1.5 times the width from the contact edge.

8. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 6, characterized in that: When selecting the force sensor range, it is necessary to estimate the icebreaking load of each model segment. The semi-theoretical and semi-empirical estimation method of the vertical destructive force of the ice layer in the surface contact icebreaking mode can be used: Where P f is the vertical failure load of the ice layer when the annular crack penetrates; N is the bending strength of the ice layer; h is the thickness of the ice layer; k is a dimensionless constant; R is the destruction radius of the ice layer, and L is the characteristic length of the ice layer, which can be calculated by the following formula: Where E is the elastic modulus of ice; υ is the Poisson's ratio of ice; ρ w is the density of water.

9. A testing system for the spatial distribution state of the underwater submersible's buoyancy and icebreaking load according to claim 1, characterized in that: The horizontal limb (3) is provided with a through hole (31).

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