A local sectional slice model for measuring ship slamming forces

Abstract

The present application relates to a kind of local segment slice model for measuring ship slamming force, including slice segment bow model, keel beam, torque sensor, keel beam clamp, sensor clamp, slamming force sensor, I-beam, keel beam sensor axial fixing device, sectional interval break rib plate, middle sensor clamp, keel beam slamming force sensor.Each segment of the slice segment bow model of the present application has independent slamming force sensor, accurately measures the slamming force of the bow model slamming concern area and the area of large curvature change of lines;Torque sensor can measure the torsional moment of segment bow model during slamming process;Three-dimensional lines of segment can help to analyze the three-dimensional effect of segment slice during slamming process, and correct the numerical results of two-dimensional slamming calculation method;Sectional interval break rib plate reinforcing model segment stiffness, prevent segment model from being deformed and flutter by huge slamming force during slamming process, maintain the rigid properties of segment model.

Description

Technical Field

[0001] This invention belongs to the field of falling body impact testing, specifically relating to a partial slice model for measuring the impact force of a ship. Background Technology

[0002] Slamming of ships in waves is a significant factor causing ship damage and affecting ship safety. When a ship moves in waves, the bow and stern are most prone to slamming flutter. Currently, partial model drop slamming tests are the primary method for studying ship slamming loads. Therefore, existing drop slamming test models generally use a three-dimensional partial model or a two-dimensional cross-sectional model created by cutting off local curves such as the bow or stern as the slamming test object. Slamming force is measured on the complete bow or stern model, and the results are compared with numerical calculations to analyze whether the ship structure is sufficiently safe.

[0003] However, most existing methods for calculating and rapidly predicting slamming force are based on two-dimensional slamming force calculations using potential flow. These methods slice the bow and stern sections of the hull, which are subject to slamming, along the ship's length, creating numerous approximately two-dimensional, flat segments. In this case, the overall slamming force upon entering the water is equivalently replaced by the process of many individual segments entering the water, and each segment's slamming force can be considered a two-dimensional slamming process. The slamming force on each segment's cross-section is calculated using two-dimensional potential flow theory, and the results are then integrated along the ship's length to obtain the overall slamming force. This method, by replacing the real three-dimensional ship with a large number of ideal two-dimensional slices, neglects the three-dimensional effects of the model's flow field, leading to deviations in the calculated slamming force for areas with significant curvature changes in the bow and stern.

[0004] In drop impact tests, the impact force of the model is one of the important input parameters for analyzing the structural response of the hull model. The test model and measurement methods must accurately reflect the magnitude of the impact force experienced during the impact. Current drop impact testing techniques can only measure the impact force based on the entire bow or stern model, and cannot accurately measure the impact force in the specific bow and stern regions of interest or areas with significant changes in hull curvature. This limits the guidance for correcting the two-dimensional slicing method's predicted impact pressure, resulting in insufficient specificity and accuracy.

[0005] There are some publicly published patents for existing segmented models, but they are not consistent with the main structure, main functions, and corresponding principles of this model. Patent CN110877670B is a broken-shaft segmented self-propelled model for ship hydroelasticity testing, characterized by including a hull system, a keel beam system, and a propulsion system; the hull system includes segmented hulls, segmented decks, and a base.

[0006] The segments of this model are segments of the whole ship model used in the hydroelasticity test, and these segment models are elastic bodies, which is inconsistent with the rigid body and partial segment model in this paper. The connection method of the segment model is inconsistent with this model, the structural and stiffness similarity requirements of the keel beam are inconsistent with this model, the measured physical quantities are inconsistent with this model, and the purpose of the invention is inconsistent with this model. Summary of the Invention

[0007] The purpose of this invention is to provide a partial slice model for measuring the impact force of a ship.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A segmented slice model for measuring the impact force of a ship includes a segmented bow model, a keel beam, a torque sensor, a keel beam clamp, a sensor clamp, an impact force sensor, an I-beam, an axial fixing device for the keel beam sensor, segmented partition ribs, a mid-section sensor clamp, and a keel beam impact force sensor.

[0010] I-beams are fixed at the bottom center of each segment of the segmented bow model. Bolt holes are provided on the I-beams for connecting the impact force sensor and the sensor fixture.

[0011] The torque sensor is inserted into the sensor fixture and fixed, and the keel beam passes through the torque sensors of each segment; the keel beam fixture is inserted between two adjacent sensor fixtures to clamp the keel beam, and the keel beam fixture and the adjacent sensor fixture are axially fixed; after the keel beam fixture is axially fixed, the upper and lower keel beam fixing bolts of the keel beam fixture are fixed to clamp the keel beam.

[0012] The keel beam clamp and the middle sensor clamp located in the middle are fixed with bolts, and then the keel beam impact force sensor is fixed on the middle sensor clamp.

[0013] The segmented spacer ribs are inserted between adjacent slice segments and fixed with waterproof adhesive.

[0014] Furthermore, the method of slicing the bow model is to cut the bow model along the cross section of the model.

[0015] Furthermore, the impact force sensor is provided with bolt holes, which are arranged corresponding to the I-beams and sensor fixtures at the bottom of each slice segment, and are fixed by impact force sensor fixing bolts.

[0016] Furthermore, the torque sensor is provided with bolt holes, which are arranged correspondingly to the sensor fixture, and it is fixed by torque sensor fixing bolts.

[0017] Furthermore, the keel beam and the keel beam clamp are fixed by keel beam fixing bolts.

[0018] Furthermore, the keel beam clamp is provided with bolt holes corresponding to the sensor clamps, and the width of the keel beam clamp is consistent with the width between the two sensor clamps, so that the keel beam clamp can be fixed to the adjacent sensor clamps using the keel beam sensor axial fixing device.

[0019] The beneficial effects of this invention are as follows:

[0020] The purpose of this invention is to overcome the problem that three-dimensional hull local models cannot accurately measure the impact force in the impact area of ​​interest and areas with large changes in hull curvature during drop impact tests. This invention provides a segmented drop impact test model by further segmenting the local model. Compared with existing technologies, the advantages of this invention are:

[0021] (1) Each segment of the segmented model has an independent impact force sensor, which can accurately measure the impact force of the bow model in the area of ​​interest and the area with large changes in profile curvature;

[0022] (2) The torque sensor is arranged in correspondence with the model segment, which can measure the torsional torque of the segment bow model during the slamming process, which is beneficial for targeted analysis of different segments;

[0023] (3) The segmented three-dimensional profile can help analyze the three-dimensional effect of the segmented slices during the slamming process and correct the numerical results of the two-dimensional slamming calculation method.

[0024] (4) The segmented partition ribs reinforce the stiffness at the segmented parts of the model, preventing deformation and flutter caused by the huge impact force during the impact, and maintaining the rigid body properties of the segmented model. This helps to reduce the measurement error of the impact force. Attached Figure Description

[0025] Figure 1 This is a top view of the overall structure of the present invention;

[0026] Figure 2 This is a front view of the internal structure of the model of the present invention;

[0027] Figure 3 This is a side view of the internal structure of the model of the present invention;

[0028] Figure 4 This is a partially enlarged view of the connection method of the internal structure of the model of the present invention. Detailed Implementation

[0029] The present invention will now be further described with reference to the accompanying drawings.

[0030] like Figures 1-4The present invention discloses a segmented slice model for measuring the impact force of a ship, comprising a segmented bow model 1, a keel beam 2, a measuring device, a fixing device, segmented partition ribs 12, and an overall monitoring mechanism 13-14; the measuring device includes a torque sensor 3, a keel beam clamp 4, a sensor clamp 5, and an impact force sensor 6; the fixing device includes an I-beam 7, a keel beam fixing bolt 8, an impact force sensor fixing bolt 9, a torque sensor fixing bolt 10, and a keel beam sensor axial fixing device 11; the overall monitoring mechanism includes a central sensor clamp 13 and a keel beam impact force sensor 14; the above-described mechanisms constitute the basic structure of the invention.

[0031] More specifically, such as Figure 1 As shown, the segmented bow model 1 is made of fiberglass (epoxy resin) material. The model is segmented by cutting a complete bow model (generally corresponding to 20%-25% of the total length of the ship, with a scale ratio of 1:30 to 1:60) into 15 segments along the cross section of the model, with a spacing of 5mm between each segment.

[0032] More specifically, a 5mm thick segmented partition rib 12 is inserted between adjacent slices of the model. The cross-sectional profile of the partition rib 12 is consistent with the cross-sectional profile of the model at the cut, ensuring that the partition rib 12 does not alter the model's profile after insertion. A square slot is cut in the center of the partition rib 12 to accommodate the keel beam 2 and the sensor without sacrificing the rib's rigidity, preventing interference between them. After inserting the partition rib 12, sufficient waterproof adhesive must be applied to the joints between the model rib and adjacent slices to seal all gaps and prevent water from entering the model. The joints on the outer surface of the model should then be sanded smooth.

[0033] More specifically, such as Figure 1 As shown in the diagram, the bow and the section aft of the bow corresponding to 2% of the ship's length, the bulbous bow in front of the bow, and the outward-flaring extension of the model are a single, continuous section without any cutting. The remaining parts of the model are divided into 14 segments. The specific cross-sectional locations of the segmentation correspond to the two-dimensional segmentation in the numerical simulation.

[0034] More specifically, such as Figure 2 and Figure 3 As shown, a sufficiently long I-beam 7 is fixed at the middle position of the bottom of each slice segment with epoxy resin (fiberglass). Bolt holes are provided on the I-beam 7 for connecting and fixing the impact force sensor 6 and the sensor clamp 5.

[0035] More specifically, the impact force sensor 6 is provided with bolt holes, which are arranged corresponding to the I-beams 7 and sensor fixtures 5 fixed at the bottom of each segment. The impact force sensor fixing bolts 9 are used for positioning and fixing, thereby realizing targeted measurement of the impact force of each segment.

[0036] More specifically, the torque sensor 3 is provided with bolt holes and is arranged correspondingly to the sensor fixture 5. It is positioned and fixed by the torque sensor fixing bolt 10, thereby realizing targeted measurement of torque in each segment.

[0037] More specifically, such as Figure 2 As shown, the keel beam 2 passes through all the torque sensors 3 and is fixed to the keel beam clamp 4 using keel beam connecting bolts 8. The keel beam clamp 4 is arranged in an appropriate position on the keel beam 2 to fix the keel beam 2.

[0038] More specifically, the keel beam clamp 4 is provided with bolt holes corresponding to the sensor clamp 5, and the width of the keel beam clamp 4 is consistent with the width of the two sensor clamps 5, so as to ensure that the keel beam clamp 4 can be fixed with the adjacent sensor clamp 5 by the keel beam sensor axial fixing device 11 composed of screws and nuts.

[0039] More specifically, the central sensor fixture 13 has bolt holes corresponding to those of the central keel beam fixture 4, both having the same width, allowing for bolt fixing. The central sensor fixture 13 also has corresponding bolt holes at its top for the keel beam impact force sensor 14. The keel beam impact force sensor 14 is fixed to the central sensor fixture 13 using bolts, thereby monitoring the overall impact force experienced by the entire model.

[0040] This invention transforms the overall impact force of the bow model into the superposition of the impact forces of each segment by slicing the bow into segments. The impact force and torsional torque of each segment are measured by arranging impact force and torsional torque sensors in each segment.

[0041] The present invention uses special bolts to fix the impact force sensor 6 through the flange of the lower part of the I-beam 2 and the sensor clamp 5, and uses special bolts to fix the torque sensor 3 through the arc groove of the upper part of the sensor clamp 5.

[0042] This invention uses a round steel pipe as the keel beam 2, which passes through all the torque sensors 3. The round pipe is used to fix each slice segment in series, maintaining the overall profile of the slice segment model consistent with the complete bow model, and preventing the model from fluttering when an impact occurs.

[0043] This invention uses bolts to fix the keel beam 2 and the central sensor clamp 13 into the model via the keel beam clamp 4. The keel beam impact force sensor 14 is fixed to the central sensor clamp 13 with bolts to measure the overall impact force of the model.

[0044] This invention inserts segmented ribs 12 at the joints of each segment, connects them with organic waterproof adhesive, and polishes the outer surface of the model to ensure the consistency and smoothness of the profile.

[0045] Installation process of this invention:

[0046] First, fix the I-beams 7 at the bottom of each segment of the segmented bow model 1. Then, fix the impact force sensor 6 and sensor clamp 5 onto the I-beams 7. Insert the torque sensor 3 into the sensor clamp 5 for fixation, and pass the keel beam 2 through all the torque sensors 3. Insert the keel beam clamp 4 between the designated sensor clamps 5 to clamp the keel beam 2, and fix the keel beam clamp 4 axially. After the keel beam clamp 4 is axially fixed, fix the upper and lower bolts of the keel beam clamp 4 to clamp the keel beam 2. After fixing the keel beam clamp 4, connect and fix the middle keel beam clamp 4 and the middle sensor clamp 13 with bolts, and then fix the keel beam impact force sensor 14 to the middle sensor clamp 13 with bolts.

[0047] After completing the above arrangement, insert the segment spacer ribs 12 between the segments and fix them with waterproof glue. Then, polish the outer surface of the ship model to a smooth finish to complete the model installation.

[0048] Once the model is installed, it can be hoisted onto the impact testing device for testing.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A segmented slice model for measuring the impact force of a ship, characterized in that: The components include a segmented bow model (1), a keel beam (2), a torque sensor (3), a keel beam fixture (4), a sensor fixture (5), an impact force sensor (6), an I-beam (7), a keel beam sensor axial fixing device (11), segmented partition ribs (12), a middle sensor fixture (13), and a keel beam impact force sensor (14). I-beams (7) are fixed at the bottom middle position of each slice segment of the segmented bow model (1). Bolt holes are provided on the I-beams (7) for connecting the impact force sensor (6) and the sensor fixture (5). The torque sensor (3) is inserted into the sensor fixture (5) and fixed, and the keel beam (2) is passed through the torque sensors (3) of each segment; the keel beam fixture (4) is inserted between two adjacent sensor fixtures (5) to clamp the keel beam (2), and the keel beam fixture (4) and the adjacent sensor fixture (5) are axially fixed; after the keel beam fixture (4) is axially fixed, the upper and lower keel beam fixing bolts (8) of the keel beam fixture (4) are fixed to clamp the keel beam (2); The keel beam clamp (4) and the middle sensor clamp (13) located in the middle are fixed with bolts, and then the keel beam impact force sensor (14) is fixed on the middle sensor clamp (13); The segmented spacer ribs (12) are inserted between adjacent slice segments and fixed with waterproof glue.

2. A partial slice model for measuring the impact force of a ship according to claim 1, characterized in that: The slicing method of the bow model (1) is to cut the bow model of the ship along the cross section of the model.

3. A partial slice model for measuring the impact force of a ship according to claim 1, characterized in that: The impact force sensor (6) is provided with bolt holes, which are arranged corresponding to the I-beam (7) and sensor fixture (5) at the bottom of each slice segment, and are fixed by impact force sensor fixing bolts (9).

4. A partial slice model for measuring the impact force of a ship according to claim 1, characterized in that: The torque sensor (3) is provided with bolt holes, which are arranged corresponding to the sensor fixture (5) and fixed by the torque sensor fixing bolt (10).

5. A partial slice model for measuring the impact force of a ship according to claim 1, characterized in that: The keel beam (2) and the keel beam clamp (4) are fixed by the keel beam fixing bolts (8).

6. A partial slice model for measuring the slamming force of a ship according to claim 1, characterized in that: The keel beam clamp (4) is provided with bolt holes corresponding to the sensor clamp (5). The width of the keel beam clamp (4) is consistent with the width between the two sensor clamps (5), so that the keel beam clamp (4) can be fixed to the adjacent sensor clamp (5) by the keel beam sensor axial fixing device (11).

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