Device and method for measuring roll exciting moment of a ship model carrying fluidized cargo

Abstract

The application discloses a device suitable for measuring roll excitation moment of a ship model loaded with fluidized cargo in the technical field of ship hydrodynamics test and ship model test technology, and comprises a pool trailer system, a wave generator and a measuring model, wherein the measuring model comprises a ship model, an inner frame and an outer frame, the bow and the stern of the ship model are provided with adjustable connecting devices rigidly connected with the end of the ship body, the adjustable connecting devices comprise flanges, the flanges comprise a bow flange and a stern flange, the bow flange and the stern flange are fixedly connected with the bow and the stern of the ship model respectively, and the bow flange and the stern flange can adjust the relative height thereof with the ship model through sliding grooves; the device further comprises rotating shafts and torque sensors, the rotating shafts comprise a bow rotating shaft and a stern rotating shaft, and the inner side of the inner frame is fixedly provided with the torque sensors at both ends, and the device can accurately measure the roll excitation moment of the ship model loaded with fluidized cargo in the seakeeping test through cooperation of the inner frame and the outer frame.

Description

Technical Field

[0001] This invention relates to the field of ship hydrodynamic testing and ship model testing technology, specifically to a device and method for measuring the roll excitation torque of a ship model carrying fluidized cargo. Background Technology

[0002] With increasing safety requirements for the transport of easily liquefiable cargo in international maritime transport, the liquefaction of Category A cargoes (cargoes at risk of liquefaction or dynamic separation) as defined in the IMSBC Code (International Maritime Solid Bulk Cargo Code) has gradually attracted attention. For easily liquefiable cargoes, which are typical Category A cargoes, their physical properties often evolve under wave excitation during maritime transport, leading to complex movement behaviors and causing the ship to generate extremely large instantaneous rolling and capsizing moments, resulting in heeling or even capsizing. Due to the complex particulate and flow characteristics of easily liquefiable cargoes, existing theoretical and numerical methods are insufficient to accurately calculate the dynamic and kinematic responses of ships carrying this type of cargo. Model testing remains an important means of ensuring the safety of maritime transport of easily liquefiable cargoes. Patent application CN201420177391.X proposes a liquid tank sloshing moment measuring device, which can measure the sloshing moment of cargoes such as fresh water. However, it has many limitations, such as difficulty in conducting tests in a water tank, simulating real-world maritime transport conditions, and using a full-ship model for testing. Currently, there is still a lack of effective testing methods to accurately measure the roll excitation moment of a full-ship model carrying easily liquefiable cargo, especially in the seakeeping test of the ship model. Summary of the Invention

[0003] The technical problem of the present invention is to provide an apparatus and method for measuring the roll excitation moment of a ship model carrying easily liquefiable cargo, so as to accurately measure the roll excitation moment of the ship model carrying easily liquefiable cargo during seakeeping tests.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a device suitable for measuring the roll excitation moment of a ship model carrying fluidized cargo, comprising a water tank trailer system, a wave generator, and a measurement model. The measurement model includes a ship model, an inner frame, and an outer frame. Adjustable connecting devices are provided at both the bow and stern of the ship model, rigidly fixed to the ends of the hull. The ship model is connected to the inner frame via the adjustable connecting devices. The inner frame is connected to the outer frame via limiting devices. The adjustable connecting devices include:

[0005] The flange includes a bow flange and a stern flange, which are fixedly connected to the bow and stern ends of the ship model, respectively. The relative height of the bow flange and the stern flange to the ship model can be adjusted by means of a sliding groove.

[0006] The rotating shaft and torque sensor include a bow rotating shaft and a stern rotating shaft. Torque sensors are fixedly installed at both ends of the inner side of the inner frame. One end of the bow rotating shaft and the stern rotating shaft are connected to the bow flange and the stern flange, respectively, and the other end is fixedly connected to the torque sensor fixed to the inner frame.

[0007] As a further embodiment of the present invention, the ship model includes a ship model body, a bow connecting device, and a stern connecting device. Both the bow connecting device and the stern connecting device are provided with sliding grooves. The bow flange and the stern flange are respectively connected to the sliding grooves located in the ship model body and the bow connecting device. The sliding grooves allow the bow flange and the stern flange to have a certain range of free adjustment space in the vertical direction.

[0008] As a further embodiment of the present invention, the main body of the ship model is composed of multiple sets of spliced ​​models. The multiple sets of spliced ​​models can be connected head-to-head between the bow connecting device and the stern connecting device to form a ship model. The spliced ​​model includes a spliced ​​model body and a connecting pin. The spliced ​​model body is provided with splicing blocks and splicing grooves on symmetrical sides. The splicing blocks can be fitted into the splicing grooves. The upper surface of the spliced ​​model body is provided with a connecting groove. After the spliced ​​models are spliced ​​together, the connecting pin can be inserted into the limiting groove. The connecting pin can penetrate the fitted splicing blocks and splicing grooves.

[0009] As a further embodiment of the present invention, the inner frame includes an inner frame body, which is a rectangular frame with an opening at the lower end. The front and rear ends of the inner frame are respectively fixedly installed with an outer flange at the front end and an outer flange at the rear end. An inner bearing at the rear end of the inner frame is provided on the inner side. The torque sensor is fixedly installed on the inner side of the front end of the inner frame. The inner frame is connected to the ship model through a bow pivot and a stern pivot.

[0010] As a further embodiment of the present invention, the outer frame includes an outer frame body, and the upper surface of the outer frame body is provided with a front connecting rod and a rear connecting rod. The upper ends of the front connecting rod and the rear connecting rod are connected to a water tank trailer system. The water tank trailer system can adjust the position and draft of the ship model in the water through the front connecting rod and the rear connecting rod.

[0011] As a further embodiment of the present invention, the inner sides of the first and last ends of the outer frame are respectively provided with an inner bearing at the first end of the outer frame and an inner bearing at the last end of the outer frame. The inner bearing at the first end of the outer frame and the inner bearing at the last end of the outer frame are respectively connected to an inner shaft at the first end of the outer frame and an inner shaft at the last end of the outer frame. One end of the inner shaft at the first end of the outer frame and the inner shaft at the last end of the outer frame are connected to a flange on the outside of the inner frame, and the other end is connected to a bearing on the inside of the outer frame.

[0012] As a further aspect of the present invention, the measurement model includes a data processor, which includes detection devices such as displacement sensors, high-speed photography, and particle image velocimetry. The formula for calculating the center of gravity offset torque is MC1(t)=mg*Δx(t)*cosΦ(t), where:

[0013] m: Cargo quality

[0014] Δx(t): Lateral centroid shift

[0015] Small angle: cosΦ≈1

[0016] As a further embodiment of the present invention, the wave generator includes a servo motor, which can drive the water tank to generate regular and irregular waves, and a six-component force sensor, which is further classified as a strain gauge torque meter, which can directly measure the hydrodynamic torque under the action of waves.

[0017] As a further embodiment of the present invention, the ship model, outer frame and inner frame are all made of high-strength stainless steel, and the bow shaft and stern shaft in the adjustable connecting device and limiting device are all subjected to strength verification, and the bearings are maintained with lubricating oil.

[0018] A method for measuring the roll excitation moment of a ship model carrying fluidized cargo, the specific steps of which are as follows:

[0019] Step 1: Adjust the position of the flange on the slide in the model ship connection device to determine the height of the model ship's roll axis;

[0020] Step 2: Connect the ship model carrying the fluidized cargo to the inner frame via a pivot shaft according to the specified working conditions;

[0021] Step 3: Connect the inner frame to the outer frame via a pivot, connect the outer frame to the water tank trailer system, adjust the height of the outer frame, and control the draft of the model boat.

[0022] Step 4: At the start of the experiment, an external load excitation is applied to the ship model, and the ship model and the inner frame rotate freely in the outer frame around the roll axis;

[0023] Step 5: Measure the roll excitation torque on the ship model using a torque sensor.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. In actual operation, this invention sets up a dual-line detection mode for empty ships and loaded ships. By comparing and analyzing the data after empty ships and loaded ships, the influence of the additional excitation torque of easily liquefied cargo movement on water transport can be quickly obtained. This reduces experimental costs, shortens experimental time, and improves experimental efficiency and repeatability.

[0026] 2. Before measurement, this invention allows adjustment of the flange position in the slide groove to ensure the rotating shaft and the ship model's roll axis are aligned. The roll excitation torque on the ship model is then measured through the inner frame equipped with a torque sensor. In this invention, the ship model is connected to the inner frame via adjustable connection devices at the bow and stern, allowing it to be connected without affecting the internal structure and layout of the ship model. Furthermore, the slide groove design makes the inner and outer frame devices suitable for different working conditions and ship models. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying 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.

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the ship model structure of the present invention;

[0030] Figure 3 This is a schematic diagram of the internal and external frame structure of the present invention;

[0031] Figure 4 This is a schematic diagram of the disassembly of the ship model in this invention;

[0032] Figure 5 This is a diagram illustrating the experimental method of the present invention.

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 1. Ship model; 101. Main body of the ship model; 102. Bow connecting device; 103. Bow flange; 104. Slide rail; 105. Stern connecting device; 106. Stern flange; 2. Inner frame; 201. Main body of the inner frame; 202. Bow pivot; 203. Torque sensor; 204. Outer flange at the bow of the inner frame; 205. Stern pivot; 206. Inner bearing at the stern of the inner frame; 207. Outer flange at the stern of the inner frame; 3. Outer frame; 301. Outer frame body; 302. Head connecting rod; 303. Tail connecting rod; 304. Inner bearing at the head of the outer frame; 305. Inner pivot at the head of the outer frame; 306. Inner pivot at the tail of the outer frame; 307. Inner bearing at the tail of the outer frame; 4. Assembly model; 401. Assembly model body; 402. Assembly block; 403. Limiting groove; 404. Insertion groove; 405. Insertion pin; 406. Assembly groove. Detailed Implementation

[0035] 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.

[0036] Please see Figures 1-5 This invention provides a technical solution: a device suitable for measuring the roll excitation moment of a ship model carrying fluidized cargo, comprising a water tank trailer system, a wave generator, and a measurement model. The measurement model includes a ship model 1, an inner frame 2, and an outer frame 3. The bow and stern of the ship model 1 are equipped with adjustable connecting devices that are rigidly fixed to the ends of the hull. The ship model is connected to the inner frame 2 via the adjustable connecting devices. The inner frame 2 is connected to the outer frame 3 via limiting devices. The adjustable connecting devices include:

[0037] The flanges include a bow flange 103 and a stern flange 106, which are fixedly connected to the bow and stern ends of the ship model, respectively. The relative height of the bow flange 103 and the stern flange 106 to the ship model can be adjusted by the slide groove 104.

[0038] The rotating shaft and torque sensor 203 include a bow rotating shaft 202 and a stern rotating shaft 205. Torque sensors 203 are fixedly installed at both ends of the inner side of the inner frame 2. One end of the bow rotating shaft 202 and the stern rotating shaft 205 are connected to the bow flange 103 and the stern flange 106 respectively, and the other end is fixedly connected to the torque sensor 203 fixed to the inner frame 2.

[0039] In operation, this invention positions the ship model 1 within the outer frame 3 and inner frame 2. The ship model 1 rotates with the inner frame 2 via an adjustable connection device. When the outer frame 3, in conjunction with the water tank trailer system, places the ship model 1 into the testing water tank, a wave generator produces water waves within the tank. These water waves cause the ship model 1 to sway within the inner frame 2, specifically, the bow shaft 202 and stern shaft 205 rotate with the inner frame 2. During this rotation, a torque sensor 203 detects the torque to measure the ship's rolling excitation torque. The rolling torque comprises wave excitation torque and additional excitation torque from the movement of easily liquefied cargo. In practical operation, this invention employs a dual-line detection mode for both empty and loaded vessels. By comparing and analyzing the data from empty and loaded vessels, the impact of the additional excitation torque from the movement of easily liquefied cargo during water transport can be quickly obtained. This rapid acquisition of the additional excitation torque from the movement of easily liquefied cargo reduces experimental costs, shortens experimental time, and improves experimental efficiency and repeatability. Before measurement, this invention allows adjustment of the flange position within the slide 104 to ensure the rotating shaft and the ship model's roll axis are aligned. The roll excitation torque on the ship model is then measured via the inner frame 2, which is equipped with a torque sensor 203. In this invention, the ship model 1 is connected to the inner frame 2 via adjustable connection devices at the bow and stern, without affecting the internal structure and layout of the ship model 1. Furthermore, the design of the slide 104 allows the inner and outer frame 3 devices to be adaptable to different working conditions and to the ship model 1.

[0040] As a further embodiment of the present invention, the ship model 1 includes a ship model body 101, a bow connecting device 102, and a stern connecting device 105. Both the bow connecting device 102 and the stern connecting device 105 are provided with sliding grooves 104. The bow flange 103 and the stern flange 106 are respectively connected to the sliding grooves 104 in the ship model body 101 and the bow connecting device 102. The sliding grooves 104 allow the bow flange 103 and the stern flange 106 to have a certain range of free adjustment space in the vertical direction.

[0041] During operation, when conducting seakeeping tests, the bow flange 103 and stern flange 106 are adjusted in the position of the slide groove 104 to ensure that the bow shaft 202 and stern shaft 205 are in the same position as the roll axis of the ship model 1, thus ensuring the accuracy of the roll excitation torque data obtained by the torque sensor.

[0042] As a further embodiment of the present invention, the ship model body 101 is composed of multiple sets of splicing models 4. The multiple sets of splicing models 4 can be connected head-to-head between the bow connecting device 102 and the stern connecting device 105 to form a ship model 1. The splicing model 4 includes a splicing model body 401 and a connecting pin 405. The splicing model body 401 is symmetrically provided with splicing blocks and splicing grooves. The splicing blocks 402 can be fitted into the splicing grooves 406. The upper surface of the splicing model body 401 is provided with a connecting groove 404. After the splicing models 4 are spliced ​​together, the connecting pin 405 can be inserted into the limiting groove 403. The connecting pin 405 can penetrate the fitted splicing blocks 402 and the splicing grooves 406.

[0043] In operation, the ship model 1 in this invention consists of multiple sets of spliced ​​models 4. In actual experiments, the bow and stern lengths of the ship model 1 can be adjusted by changing the number of spliced ​​models 4. In specific experiments, the number of spliced ​​models 4 can be gradually increased to control variables and detect the influence of ship length on roll moment, so as to make the detection data diverse and ensure that multiple variables do not interfere with roll moment.

[0044] As a further embodiment of the present invention, the inner frame 2 includes an inner frame body 201, which is a rectangular frame with an opening at the lower end. The front and rear ends of the inner frame are respectively fixedly installed with an outer flange 204 at the front end and an outer flange 207 at the rear end. An inner bearing 206 at the rear end of the inner frame is provided on the inner side. A torque sensor 203 is fixedly installed on the inner side of the front end of the inner frame 2. The inner frame 2 is connected to the ship model 1 through a bow pivot 202 and a stern pivot 205.

[0045] During operation, in the water tank test of this invention, after the overall model is installed, wave excitation is carried out. The inner frame 2 starts to move with the support of the outer frame 3. The ship model 1 receives wave load excitation. The easily liquefiable cargo inside the ship model 1 is subjected to external load excitation, which produces a reaction effect on the movement of the ship model system and generates a coupling effect. At the same time, the torque sensor records the excitation torque on the ship model.

[0046] As a further embodiment of the present invention, the outer frame 3 includes an outer frame body 301. The upper surface of the outer frame body 301 is provided with a head connecting rod 302 and a tail connecting rod 303. The upper ends of the head connecting rod 302 and the tail connecting rod 303 are connected to the water tank trailer system. The water tank trailer system can adjust the position and draft of the ship model 1 in the water through the head connecting rod 302 and the tail connecting rod 303.

[0047] During operation, the separate design of the outer frame 3 and the inner frame 2 in this invention allows the inner and outer frames to be freely matched, and the device can be reasonably selected according to the conditions of the pool. At the same time, the inner and outer frames can be combined to adapt to complex working conditions.

[0048] As a further embodiment of the present invention, the inner sides of the first and last ends of the outer frame 3 are respectively provided with an inner bearing 304 at the first end and an inner bearing 307 at the last end of the outer frame. The inner bearing 304 at the first end and the inner bearing 307 at the last end of the outer frame are respectively connected to an inner shaft 305 at the first end and an inner shaft 306 at the last end of the outer frame. One end of the inner shaft 305 at the first end and the inner shaft 306 at the last end of the outer frame are connected to the flange on the outside of the inner frame 2, and the other end is connected to the bearing on the inside of the outer frame 3.

[0049] During operation, the separate design of the outer frame 3 and the inner frame 2 in this invention allows the inner and outer frames to be freely matched, and the device can be reasonably selected according to the conditions of the pool. At the same time, the inner and outer frames can be combined to adapt to complex working conditions.

[0050] As a further aspect of the present invention, the measurement model includes a data processor, which includes detection devices such as displacement sensors, high-speed photography, and particle image velocimetry. The formula for calculating the center of gravity offset torque is MC1(t)=mg*Δx(t)*cosΦ(t), where:

[0051] m: Cargo quality

[0052] Δx(t): Lateral centroid shift (fluidized sliding displacement)

[0053] Small angle: cosΦ≈1.

[0054] During operation, this invention uses torque sensor 203 as the basis for detection data, while also setting up detection equipment such as displacement sensor, high-speed photography and particle image velocimetry to calculate the center of gravity offset moment of the ship. The center of gravity offset moment is a major component of the additional excitation moment for the movement of easily liquefied cargo. By comparing the two sets of detection data, the accuracy of the detection data can be ensured.

[0055] As a further embodiment of the present invention, the wave generator includes a servo motor, which can drive the water tank to generate regular and irregular waves, and a six-component force sensor, which is further classified as a strain gauge torque meter, which can directly measure the hydrodynamic torque under the action of waves.

[0056] In this invention, regular and irregular waves are generated in a water tank using a wave generator. By comparing the difference in the additional excitation torque of the easily fluidized cargo movement of the ship model under the two wave states, the diversity of detection data is increased.

[0057] As a further embodiment of the present invention, the ship model 1, the outer frame 3 and the inner frame 2 are all made of high-strength stainless steel. The bow shaft 202 and the stern shaft 205 in the adjustable connection device and the limiting device are all subjected to strength verification, and the bearings are maintained with lubricating oil.

[0058] A method for measuring the roll excitation moment of a ship model carrying fluidized cargo, the specific steps of which are as follows:

[0059] Step 1: Adjust the position of the flange on the slide in the model ship connection device to determine the height of the model ship's roll axis;

[0060] Step 2: Connect the ship model 1 carrying fluidized cargo to the inner frame 2 via a pivot shaft according to the specified working conditions;

[0061] Step 3: Connect the inner frame 2 to the outer frame via a pivot, connect the outer frame to the water tank trailer system, adjust the height of the outer frame, and control the draft of the model boat.

[0062] Step 4: At the start of the experiment, an external load wave excitation is applied to ship model 1, and ship model 1 and inner frame 2 rotate freely in outer frame 3 around the roll axis;

[0063] Step 5: Measure the roll excitation torque on the ship model using torque sensor 203.

[0064] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device for measuring the roll excitation moment of a model ship carrying fluidized cargo, comprising a water tank trailer system, a wave generator, and a measurement model, characterized in that: The measurement model includes a ship model (1), an inner frame (2), and an outer frame (3). The ship model (1) has adjustable connecting devices at both its bow and stern, which are rigidly fixed to the ends of the hull. The ship model is connected to the inner frame (2) via these adjustable connecting devices. The inner frame (2) is connected to the outer frame (3) via limiting devices. The adjustable connecting devices include: The flange includes a bow flange (103) and a stern flange (106), which are fixedly connected to the bow and stern ends of the ship model, respectively. The relative height of the bow flange (103) and the stern flange (106) with respect to the ship model can be adjusted by means of a slide groove (104). The rotating shaft and torque sensor (203) include a bow rotating shaft (202) and a stern rotating shaft (205). Torque sensors (203) are fixedly installed at both ends of the inner side of the inner frame (2). One end of the bow rotating shaft (202) and the stern rotating shaft (205) are connected to the bow flange (103) and the stern flange (106) respectively, and the other end is fixedly connected to the torque sensor (203) fixed to the inner frame (2).

2. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 1, characterized in that: The ship model (1) includes a ship model body (101), a bow connection device (102) and a stern connection device (105). Both the bow connection device (102) and the stern connection device (105) are provided with a sliding groove (104). The bow flange (103) and the stern flange (106) are respectively connected in the sliding groove (104) of the ship model body (101) and the bow connection device (102). The sliding groove (104) allows the bow flange (103) and the stern flange (106) to have a certain range of free adjustment space in the vertical direction.

3. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 2, characterized in that: The ship model body (101) is composed of multiple sets of splicing models (4). The multiple sets of splicing models (4) can be connected head-to-head between the bow connecting device (102) and the stern connecting device (105) to form a ship model (1). The splicing model (4) includes a splicing model body (401) and a plug pin (405). The splicing model body (401) is provided with splicing blocks and splicing grooves on symmetrical sides. The splicing blocks (402) can be fitted into the splicing grooves (406). The upper surface of the splicing model body (401) is provided with a plug groove (404). After the splicing models (4) are spliced ​​together, the plug pin (405) can be inserted into the limiting groove (403). The plug pin (405) can penetrate the fitted splicing blocks (402) and splicing grooves (406).

4. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 3, characterized in that: The inner frame (2) includes an inner frame body (201), which is a rectangular frame with an opening at the bottom. The front and rear ends of the inner frame are respectively fixedly installed with an outer flange (204) at the front and an outer flange (207) at the rear. An inner bearing (206) at the rear of the inner frame is provided on the inner side of the rear. The torque sensor (203) is fixedly installed on the inner side of the front of the inner frame (2). The inner frame (2) is connected to the ship model (1) through a bow pivot (202) and a stern pivot (205).

5. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 4, characterized in that: The outer frame (3) includes an outer frame body (301). The upper surface of the outer frame body (301) is provided with a bow connecting rod (302) and a tail connecting rod (303). The upper ends of the bow connecting rod (302) and the tail connecting rod (303) are connected to the water tank trailer system. The water tank trailer system can adjust the position and draft of the ship model (1) in the water through the bow connecting rod (302) and the tail connecting rod (303).

6. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 5, characterized in that: The outer frame (3) is provided with an inner bearing (304) at the head and an inner bearing (307) at the tail, respectively. The inner bearing (304) at the head and the inner bearing (307) at the tail are respectively connected to an inner shaft (305) at the head and an inner shaft (306) at the tail. One end of the inner shaft (305) at the head and the inner shaft (306) at the tail are connected to the flange on the outside of the inner frame (2), and the other end is connected to the bearing on the inside of the outer frame (3).

7. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 5, characterized in that: The measurement model includes a data processor, which includes detection devices such as displacement sensors, high-speed photography, and particle image velocimetry. The formula for calculating the center of gravity offset moment is MC1(t) = mg * Δx(t) * cosΦ(t), where: m: Cargo quality Δx(t): Lateral centroid shift (fluidized sliding displacement) Small angle: cosΦ≈1.

8. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 5, characterized in that: The wave generator includes a servo motor that can drive the water tank to generate regular and irregular waves, and a six-component force sensor, which is then a strain gauge torque meter, that can directly measure the hydrodynamic torque under the action of waves.

9. The device for measuring the roll excitation torque of a ship model carrying fluidized cargo according to claim 5, characterized in that: The ship model (1), outer frame (3) and inner frame (2) are all made of high-strength stainless steel. The bow shaft (202) and stern shaft (205) in the adjustable connection device and limiting device are all strength checked, and the bearings are maintained with lubricating oil.

10. A method for measuring the roll excitation moment of a model ship carrying liquefied cargo, applicable to the apparatus for measuring the roll excitation moment of a model ship carrying liquefied cargo as described in any one of claims 1-9, wherein the specific steps of the measurement method are as follows: Step 1: Adjust the position of the flange on the slide in the model ship connection device to determine the height of the model ship's roll axis; Step 2: Connect the ship model (1) carrying fluidized cargo to the inner frame (2) via a pivot shaft according to the specified working conditions. Step 3: Connect the inner frame (2) to the outer frame via a pivot, connect the outer frame to the water tank trailer system, adjust the height of the outer frame, and control the draft of the model boat. Step 4: At the start of the experiment, an external load (wave) excitation is applied to the ship model (1), and the ship model (1) and the inner frame (2) rotate freely in the outer frame (3) around the roll axis; Step 5: Measure the roll excitation torque on the ship model using the torque sensor (203).

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