Method for measuring and calculating buoyancy reserve coefficient of multipurpose vehicle

Abstract

The invention discloses a method for measuring and calculating a buoyancy reserve coefficient of a multi-purpose vehicle. The method comprises the following steps: step 1, acquiring a proportional relation between the multi-purpose vehicle and a corresponding three-dimensional model; 2, carrying out a full-load test on the vehicle in a still water state, and obtaining the mass of the vehicle in the full-load state and the actual freeboard height; 3, obtaining a corresponding model freeboard height in the three-dimensional model according to the actual freeboard height and the proportional relation, and measuring and calculating a model buoyancy reserve volume under the proportion of the three-dimensional model according to the model freeboard height; and 4, obtaining the buoyancy reserve coefficient of the multipurpose vehicle according to the model buoyancy reserve volume, the mass of the vehicle in the full load state and the proportional relation. According to the method, data capable of being accurately measured can be obtained from the vehicle, the data obtaining precision is guaranteed, and the requirement for high-precision measurement of the buoyancy reserve coefficient of the multipurpose vehicle is met.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-purpose vehicle testing, and particularly relates to a method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle. Background Art

[0002] Multi-purpose vehicles combine the dual performance of vehicles and ships. They can travel on land like cars and can also float and cross water like ships. Due to their excellent land and water passage performance, they can cross rivers, lakes, and seas during travel without being restricted by bridges or ships, so they have special historical significance in transportation and are mostly used in professional fields such as military, disaster relief, and exploration.

[0003] In the design stage of multi-purpose vehicles, in order to meet their actual application requirements, especially to ensure maritime navigation safety, parameters such as the unladen weight and laden weight of multi-purpose vehicles need to be comprehensively considered to enable multi-purpose vehicles to meet the buoyancy reserve requirements for water travel.

[0004] In the inspection stage of multi-purpose vehicles, in order to ensure that their buoyancy reserve coefficient meets the design specifications, it is necessary to test the buoyancy reserve of the actual vehicle. Currently, for the test of buoyancy reserve, relevant measurement methods have been formed in the domestic and foreign shipbuilding industries, and the test of the buoyancy reserve of multi-purpose vehicles basically draws on the methods of the shipbuilding industry. However, due to the relatively complex shape of multi-purpose vehicles compared with ships, the existing ship buoyancy reserve measurement and calculation methods cannot meet the high-precision measurement requirements for the buoyancy reserve coefficient of multi-purpose vehicles. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle to solve the problem that the existing ship buoyancy reserve measurement and calculation methods cannot meet the high-precision measurement requirements for the buoyancy reserve coefficient of multi-purpose vehicles.

[0006] To achieve the above purpose, the method of the present invention calculates the buoyancy reserve coefficient of a multi-purpose vehicle by simultaneously using the multi-purpose vehicle entity and the corresponding three-dimensional model. Specifically, the method includes the following steps:

[0007] Step 1: Obtain the proportional relationship between the multi-purpose vehicle and its corresponding three-dimensional model;

[0008] Step 2: Conduct a full-load test on the vehicle under static water conditions to obtain the mass and actual freeboard height of the multi-purpose vehicle in the full-load state;

[0009] Step 3: Obtain the corresponding model freeboard height in the three-dimensional model according to the actual freeboard height and the proportional relationship, and calculate the model buoyancy reserve volume under the three-dimensional model scale according to the model freeboard height;

[0010] Step 4: Obtain the buoyancy reserve coefficient of the multi-purpose vehicle based on the model buoyancy reserve volume, the mass of the vehicle under the fully loaded state, and the proportional relationship.

[0011] Based on the above, in Step 1, the proportional relationship is obtained by measuring the external dimensions of the vehicle and the external dimensions of its corresponding three-dimensional model.

[0012] In the present invention, the proportional relationship is obtained by means of the external dimensions of the multi-purpose vehicle and its corresponding three-dimensional model. This obtaining method increases the accuracy of obtaining the proportional relationship compared with the method of obtaining it from the height or width ratio. Although the proportional relationship has been determined during the setting process of the three-dimensional model and its corresponding multi-purpose vehicle, in actual production, due to the reasons of the manufacturing process, the proportional relationship will change slightly. Therefore, the actual measurement process further ensures the accuracy of obtaining the proportional relationship, and thus ensures the buoyancy reserve coefficient of the finally obtained multi-purpose vehicle.

[0013] Based on the above, in Step 1, the three-dimensional model is a solid three-dimensional model, and the positions of the external movable mechanisms in the three-dimensional model are consistent with those of the multi-purpose vehicle when it is on the water.

[0014] In order to meet the high-precision measurement requirements of the buoyancy reserve coefficient of the multi-purpose vehicle, the three-dimensional model used in the present invention is a solid three-dimensional model, and the positions of the external movable mechanisms of the three-dimensional model are made consistent with those of the vehicle when it is on the water. In this way, there are only proportional differences between the three-dimensional model and the corresponding vehicle, and thus the actual information of the multi-purpose vehicle can be accurately obtained based on the information under the three-dimensional model and the proportional relationship.

[0015] Based on the above, in Step 2, the freeboard measurement reference plane and the waterline scale are pre-marked on the vehicle, and during the full-load test, the position of the waterline plane on the waterline scale of the vehicle is read, and the actual freeboard height is obtained based on the position of the waterline plane and the freeboard measurement reference plane.

[0016] In the present invention, considering that the actual freeboard height refers to the vertical distance from the full-load waterline to the upper edge of the deck in the middle of the ship, in order to facilitate obtaining the accurate freeboard value, the freeboard measurement reference plane and the waterline scale are pre-set in the present invention, so that the vertical distance from the full-load waterline to the upper edge of the deck in the middle of the ship can be obtained conveniently and accurately, avoiding the influence of human factors on the result when there is no standard set, and further increasing the accuracy of data acquisition.

[0017] Based on the above, in Step 2, the freeboard measurement reference plane is confirmed according to the position of the lowest sealed window or the horizontal top deck of the vehicle.

[0018] In the present invention, it is considered that the minimum freeboard of a multi-purpose vehicle in water is the limit to ensure the safe floating of the ship on the water surface. If the ship is overloaded and the freeboard is reduced to less than the specified limit, the ship cannot float safely on the water surface. Therefore, the minimum freeboard is also called the safety freeboard. Thus, in order to ensure the accuracy of data under actual conditions, in the present invention, the freeboard measurement reference plane is determined by the lowest sealing window position or the horizontal top deck position of the multi-purpose vehicle.

[0019] Based on the above, in step 2, the waterline scale includes 4 waterline scales respectively drawn on the front, rear, left, and right of the vehicle. In step 3, a first plane is established on the three-dimensional model according to the intersection positions of the 4 waterline scales and the waterline plane, and the plane is translated upward by a translation distance equal to the freeboard height of the model to obtain a second plane. The volume of the three-dimensional model of the intercepted part between the two planes is measured as the buoyancy reserve volume V of the model.

[0020] The waterline scale in the present invention is set to at least four and includes four faces of the vehicle. Therefore, establishing a first plane on the three-dimensional model according to the intersection positions of the 4 waterline scales and the waterline plane is the fully loaded draft line obtained from the fully loaded test that accurately simulates the vehicle in the still water state. Furthermore, the accuracy of the data obtained through this accurate simulation process is also guaranteed.

[0021] Based on the above, in step 4, first, the simulated buoyancy reserve coefficient is obtained according to the buoyancy reserve volume of the model and the mass of the vehicle in the fully loaded state, and then the buoyancy reserve coefficient of the multi-purpose vehicle is obtained by correcting the simulated buoyancy reserve coefficient according to the proportional relationship.

[0022] Based on the above, the calculation formula for the simulated buoyancy reserve coefficient σ is:

[0023] σ = ρV / G * 100%

[0024] Where ρ is the density of water and G is the mass of the multi-purpose vehicle in the fully loaded state.

[0025] In the present invention, by first calculating using simulated data and then converting using the proportional relationship, the buoyancy reserve coefficient of the actual multi-purpose vehicle is finally obtained. Since this process is a process of calculating using three-dimensional model data, the calculated data is smaller, simplifying the data in the calculation process. And based on the reduction of the data value, the calculation accuracy can be improved, and thus the high-precision measurement requirements for the buoyancy reserve coefficient of the multi-purpose vehicle can be met.

[0026] Based on the above, in step 4, first, the buoyancy reserve volume of the model is converted into the actual buoyancy reserve volume of the vehicle according to the proportional relationship, and then the buoyancy reserve coefficient of the multi-purpose vehicle is obtained according to the actual buoyancy reserve volume and the mass of the vehicle in the fully loaded state.

[0027] In the present invention, the data is first converted to an actual multi-purpose vehicle by using a proportional relationship, and then the buoyancy reserve coefficient of the vehicle is directly obtained by using the data of the actual vehicle. Since the data is first converted to the data of the vehicle, all the data used is the data of the multi-purpose vehicle, and this process conforms to the actual calculation situation.

[0028] Based on the above, the still water state in step 2 includes: the ambient wind speed is below 3 m / s, the water surface wave height is below 20 mm, and the water surface flow velocity is below 0.5 m / s.

[0029] In the present invention, regulations are also set for the still water state, that is, in the present invention, considering that the ambient wind speed, the water surface wave height, and the water surface flow velocity will all affect the accuracy of the full-load test, the accuracy of the data obtained by conducting the test under specific conditions of the present invention is higher.

[0030] The method of the present invention has the following advantages:

[0031] The method of the present invention can obtain the accurately measurable data from the vehicle by using the multi-purpose vehicle and the corresponding three-dimensional model at the same time, and obtain the data that is not easy to obtain or has errors when obtaining from the corresponding three-dimensional model, and then correct the data obtained from the three-dimensional model to the data of the multi-purpose vehicle according to the proportional relationship between the vehicle and the three-dimensional model, thereby ensuring the accuracy of data acquisition to meet the high-precision measurement requirements of the buoyancy reserve coefficient of the multi-purpose vehicle.

[0032] The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given and described in detail in conjunction with the drawings. Description of the Drawings

[0033] Figure 1 It is a flowchart of the method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle. Detailed Embodiment

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with specific implementation schemes. However, those skilled in the art should understand that the implementation schemes described below are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the implementation schemes in the present invention, all other implementation schemes obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0035] Embodiment of the Method for Calculating the Buoyancy Reserve Coefficient of a Multi-purpose Vehicle

[0036] The method of this embodiment proposes a method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle to meet the test requirements of the buoyancy reserve coefficient of the multi-purpose vehicle in still water, and forms a set of data measurement and calculation methods to provide data support for the verification of the buoyancy reserve coefficient of the multi-purpose vehicle. This method has good operability and high accuracy. Specifically, by simultaneously using the multi-purpose vehicle and its corresponding three-dimensional model, the data that can be accurately measured is obtained from the vehicle, while the data that is difficult to obtain or has errors when obtained is obtained from the corresponding three-dimensional model. Then, according to the proportional relationship between the vehicle and the three-dimensional model, the data obtained from the three-dimensional model is corrected to the data of the multi-purpose vehicle, thereby ensuring the accuracy of data acquisition to meet the high-precision measurement requirements of the buoyancy reserve coefficient of the multi-purpose vehicle.

[0037] The method of this embodiment includes the following steps:

[0038] Step 1: Obtain the proportional relationship between the multi-purpose vehicle and its corresponding three-dimensional model.

[0039] The proportional relationship of this embodiment is obtained by measuring the external dimensions of the vehicle and the external dimensions of its corresponding three-dimensional model. The three-dimensional model used is a solid three-dimensional model, and the positions of the external moving mechanisms in the three-dimensional model are the same as those of the multi-purpose vehicle when it is on the water.

[0040] Compared with the method of obtaining the proportional relationship from the height or width ratio, the way of obtaining the proportional relationship in this embodiment increases the accuracy of obtaining the proportional relationship and avoids the slight change of the proportional relationship determined during production due to the manufacturing process. Therefore, the actual measurement process further ensures the accuracy of obtaining the proportional relationship. And to meet the high-precision measurement requirements of the buoyancy reserve coefficient of the multi-purpose vehicle, this embodiment is a solid three-dimensional model, and the positions of the external moving mechanisms of the three-dimensional model are the same as those of the vehicle when it is on the water, so that there are only proportional differences between the three-dimensional model and the corresponding vehicle. Furthermore, the actual information of the vehicle can be accurately obtained according to the information under the three-dimensional model and the proportional relationship, so as to ensure the final buoyancy reserve coefficient of the multi-purpose vehicle.

[0041] Step 2: Conduct a full-load test on the vehicle in a still water state to obtain the mass and the actual freeboard height of the multi-purpose vehicle in the full-load state.

[0042] In this embodiment, the freeboard measurement reference plane and the waterline scale are pre-marked on the vehicle, and the position of the waterline plane on the waterline scale of the vehicle is read during the full-load test. The actual freeboard height is obtained according to the position of the waterline plane and the freeboard measurement reference plane. To ensure the accuracy of the data under actual conditions, the freeboard measurement reference plane is determined according to the lowest sealed window position or the horizontal top deck position of the vehicle. The waterline scale includes 4 waterline scales drawn on the front, rear, left, and right of the vehicle respectively.

[0043] To facilitate obtaining accurate freeboard values, in this embodiment, a freeboard measurement reference plane and a waterline scale are preset to conveniently and accurately obtain the vertical distance from the full-load waterline to the upper edge of the deck in the middle of the ship, avoiding the influence of human factors and errors caused by different standards, and increasing the accuracy of data acquisition.

[0044] This embodiment takes into account that environmental wind speed, water surface wave height, and water surface flow velocity will all affect the accuracy of the full-load test. Therefore, the still water state in this embodiment includes that the test environmental wind speed is not greater than 3 m / s, the water surface wave height is not greater than 20 mm, and the water surface flow velocity is not greater than 0.5 m / s. This makes the data obtained from the test under the specific conditions of this embodiment more accurate.

[0045] Step 3: Obtain the corresponding model freeboard height in the three-dimensional model according to the actual freeboard height and the proportional relationship, and calculate the model buoyancy reserve volume under the three-dimensional model scale based on the model freeboard height.

[0046] In this embodiment, a first plane is established on the three-dimensional model according to the intersection positions of 4 waterline scales and the waterline surface, and the plane is translated upward by a translation distance equal to the model freeboard height to obtain a second plane. The volume of the intercepted part between the two planes of the three-dimensional model is measured as the model buoyancy reserve volume V.

[0047] The waterline scales in this embodiment are set to at least four and include the four faces of a multi-purpose vehicle. Therefore, establishing a first plane on the three-dimensional model according to the intersection positions of these 4 waterline scales and the waterline surface accurately simulates the full-load waterline obtained from the full-load test of the multi-purpose vehicle in the still water state, thereby ensuring the accuracy of the data obtained through this accurate simulation process.

[0048] Step 4: Obtain the buoyancy reserve coefficient of the multi-purpose vehicle according to the model buoyancy reserve volume, the mass of the vehicle in the full-load state, and the proportional relationship.

[0049] The method for obtaining the buoyancy reserve coefficient in this embodiment is as follows: First, obtain the simulated buoyancy reserve coefficient according to the model buoyancy reserve volume V and the mass of the vehicle in the full-load state, and then correct the simulated buoyancy reserve coefficient according to the proportional relationship to obtain the buoyancy reserve coefficient of the multi-purpose vehicle. The calculation formula for the simulated buoyancy reserve coefficient σ (unit: %) is: σ = ρV / G * 100%, where ρ is the density of water (in this embodiment, 0.001 kg / cm 3 ), V is the model buoyancy reserve volume (unit: cm 3 ), and G is the mass of the multi-purpose vehicle in the full-load state (unit: kg).

[0050] First, calculate using simulated data, and then convert using proportional relationships to finally obtain the buoyancy reserve coefficient of the actual multi-purpose vehicle. This process is a calculation process using three-dimensional model data. Therefore, the amount of calculation data is small, the data in the calculation process is simplified, and based on the reduction of data values, the calculation accuracy can be improved, thereby meeting the high-precision measurement requirements for the buoyancy reserve coefficient of multi-purpose vehicles.

[0051] As another implementation, the buoyancy reserve volume of the model can be first converted to the actual buoyancy reserve volume of the vehicle according to the proportional relationship, and then the buoyancy reserve coefficient of the multi-purpose vehicle can be obtained based on the actual buoyancy reserve volume and the mass of the vehicle under the fully loaded state.

[0052] First, convert the data to the actual vehicle using the proportional relationship, and then directly obtain the buoyancy reserve coefficient of the multi-purpose vehicle using the data of the actual vehicle, so that all the data used in the final calculation are the data of the multi-purpose vehicle, and this process conforms to the actual situation.

[0053] The method of this embodiment can measure and calculate the buoyancy reserve coefficient of multi-purpose vehicles, provide a basis for evaluating the buoyancy reserve performance of multi-purpose vehicles, and can be applied to the buoyancy reserve measurement of other waterborne vessels.

[0054] Although the present invention has been described in detail with general descriptions and specific embodiments above, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle, characterized in that: The steps include: Step 1, obtaining a proportional relationship between a multi-purpose vehicle and its corresponding three-dimensional model; Step 2: Conduct a full-load test on the vehicle in still water to obtain the vehicle's mass and actual freeboard height under full-load condition; Step 3: obtaining a corresponding model freeboard height in the three-dimensional model according to the actual freeboard height and the proportional relationship, and obtaining a model buoyancy reserve volume at the three-dimensional model scale according to the model freeboard height; Step 4: Obtain the buoyancy reserve coefficient of the multi-purpose vehicle according to the model buoyancy reserve volume, the mass of the vehicle in a fully loaded state, and the proportional relationship.

2. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 1, characterized in that: In step 1, the proportional relationship is obtained by measuring the outer dimensions of the vehicle and the outer dimensions of its corresponding three-dimensional model.

3. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 2, characterized in that: In step 1, the three-dimensional model is a solid three-dimensional model, and the positions of the external movable mechanisms in the three-dimensional model are consistent with those of the multi-purpose vehicle when it is on water.

4. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 1, characterized in that: In step 2, the freeboard measurement reference plane and the waterline scale are marked on the vehicle in advance, and the waterline scale position of the waterplane on the vehicle is read during the full load test, and the actual freeboard height is obtained based on the waterplane position and the freeboard measurement reference plane.

5. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 4, characterized in that: In step 2, the freeboard measurement reference plane is determined according to the lowest sealed window position or the horizontal top deck position of the vehicle.

6. The method for calculating the vehicle buoyancy reserve coefficient according to claim 4, characterized in that: In step 2, the waterline scale includes four waterline scales drawn in front, behind, left and right of the vehicle respectively. In step 3, a first plane is established on the three-dimensional model according to the intersection positions of the four waterline scales and the waterline plane, and the plane is translated upward by a distance equal to the model freeboard height to obtain a second plane. The volume of the three-dimensional model intercepted between the two planes is measured as the model buoyancy reserve volume V.

7. The method for calculating the vehicle buoyancy reserve coefficient according to claim 6, characterized in that: In step 4, the simulated buoyancy reserve coefficient is first obtained according to the model buoyancy reserve volume and the mass of the vehicle in a fully loaded state, and then the simulated buoyancy reserve coefficient is corrected according to the proportional relationship to obtain the buoyancy reserve coefficient of the multi-purpose vehicle.

8. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 7, characterized in that: The calculation formula of the simulated buoyancy reserve coefficient σ is: σ=ρV / G*100%; Where ρ is the density of water and G is the mass of the multi-purpose vehicle when fully loaded.

9. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 6, characterized in that: In step 4, the model buoyancy reserve volume is first converted into the actual buoyancy reserve volume of the vehicle according to the proportional relationship, and then the buoyancy reserve coefficient of the multi-purpose vehicle is obtained according to the actual buoyancy reserve volume and the mass of the vehicle in a fully loaded state.

10. The method for calculating the buoyancy reserve coefficient of a multi-purpose vehicle according to claim 1, characterized in that: The still water state in step 2 includes: the ambient wind speed is below 3 m / s, the water surface wave height is below 20 mm, and the water surface flow velocity is below 0.5 m / s.

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