Barge type depth determination method based on structural weight control

Abstract

The invention provides a barge type depth determination method based on structure weight control, and the method comprises the steps: considering the sensitivity of a transverse section modulus and a section inertia moment in a barge to the change of the type depth, adjusting the type depth, carrying out the structural design, checking the total longitudinal strength, and calculating the structure weight, so as to obtain the optimal type depth which meets the standard requirements and is the lightest in structure weight. The problems that an existing barge structure is too heavy in weight and consumes a large amount of steel, loading is reduced when the displacement is fixed, more ship resources are occupied, and economy is not achieved are solved, and barge type depth value selection with the lightest structure weight is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of ship design engineering, and in particular to a method for determining the molded depth of a barge based on structure weight control. Background Art

[0002] Barges are commonly used for cargo transportation in rivers, canals, and river estuaries. They are characterized by simple equipment, shallow draft, and large cargo capacity. The width-to-depth ratio of barges is large, and the ship is wide and flat. For example, the length, width, and depth of a self-propelled barge are 77.3m, 20m, and 4.6m respectively, and the ratio of width to depth reaches 4.35.

[0003] In current barge design, the main dimensions (including molded depth) are usually determined based on overall performance such as ship type, cargo capacity, and speed, in accordance with design specifications or parent ships.

[0004] In the design of barge hull structure, in order to meet the requirements of total longitudinal strength, the modulus and moment of inertia of the cross-section of the hull structure are often required to reach a certain value, and the section modulus and moment of inertia are very sensitive to the mold depth. If the mold depth is too small, in order to meet the section modulus and moment of inertia, the structure needs to use a larger plate thickness and frame, which increases the weight significantly. If the mold depth is too large, the section modulus and moment of inertia are easier to meet the requirements, but the larger depth will bring a larger overall structure frame and increase the weight. The weight of the structure changes with the mold depth. Figure 1 shown.

[0005] Considering the depth from the perspective of overall performance without considering the structural weight factor often leads to a large proportion of structural weight, which occupies too many ship resources. Although its design meets the requirements of the specifications, on the one hand, the structural weight is large, consumes more steel, and appears bulky; on the other hand, when the displacement and other equipment remain unchanged, the empty ship weight is large, the cargo capacity is reduced, and it is not economical. Referring to the coastal or inland barges currently in use, their depth and freeboard are small, the plate thickness and frame size are large, and the structural weight accounts for more than 80% of the empty ship weight. The structural strength margin is too much, and there is a large room for optimization of the hull structure.

[0006] Therefore, it is necessary to adopt measures to determine the draft of the barge based on the control of the structural weight and select the draft that makes the structural weight the lightest, which can not only meet the requirements of the specifications, but also reduce the structural weight, reduce capital waste and increase economic benefits. Summary of the invention

[0007] The technical problem to be solved by the technical solution of the present invention is that the main dimensions (including the depth) in the current barge design are usually determined according to the overall performance such as ship type, cargo capacity, rapidity, etc., in accordance with the design specifications or the parent ship. If the structural weight factor is not considered, it often leads to an excessive proportion of structural weight, which occupies too many ship resources, causing waste and being uneconomical.

[0008] In order to solve the above technical problems, the technical solution of the present invention provides a method for determining the depth of a barge based on structural weight control, comprising the following steps:

[0009] Step 1: According to the design specifications or the parameters of the parent ship combined with the overall performance requirements, the main dimensions of the barge are preliminarily determined. The main dimensions of the barge include the length, width, depth, square coefficient and material coefficient;

[0010] Step 2: Based on the general arrangement drawing, determine the barge mid-section structure layout, the barge mid-section structure skeleton form, and the frame spacing of each plate in the barge mid-section to obtain the initial structure layout drawing;

[0011] Step 3: According to the initial structural layout, the initial plate thickness and longitudinal bone size are selected in combination with the preset minimum plate thickness and frame modulus. The minimum section modulus and the minimum section moment of inertia are obtained according to the total longitudinal strength verification formula combined with the main dimensions of the barge. The total longitudinal strength verification of the initial longitudinal girder size and the strong crossbeam size is carried out according to the minimum section modulus and the minimum section moment of inertia to adjust the plate thickness, longitudinal bone size and longitudinal girder size;

[0012] Step 4: Calculate the weight of the hull structure corresponding to the depth according to the adjusted plate thickness, longitudinal bone size, longitudinal girder size and general arrangement drawing;

[0013] Step 5: Repeat steps 3 and 4 to change the draft depth to obtain different draft depths and the corresponding hull structure weights. Use different draft depths as the horizontal coordinates and the corresponding hull structure weights as the vertical coordinates. Use quadratic and cubic polynomials to fit respectively to obtain the draft depth with the minimum structure weight.

[0014] Preferably, the cross-sectional structural arrangement of the barge includes the positions of the main deck, the bottom plate, the side outer plate, the platform deck and the longitudinal bulkhead.

[0015] Preferably, the cross-sectional structural skeleton form of the barge includes a longitudinal skeleton type.

[0016] Preferably, the spacing between the frame members of each plate in the cross section of the barge ranges from 200 mm to 700 mm.

[0017] Preferably, the spacing between aggregates is determined based on construction convenience, welding residual deformation, plate thickness and aggregate size, combined with the aggregate spacing range.

[0018] Preferably, the spacing between the aggregates is selected to be 400 mm.

[0019] Preferably, the total longitudinal strength verification formula includes a minimum section modulus formula and a minimum section moment of inertia formula.

[0020] Preferably, the minimum section modulus formula is:

[0021] W 0 =CL 2 B(C b +0.7)K

[0022] Among them, C represents the coefficient, L represents the length of the ship, B represents the width of the ship, and C b represents the square coefficient, and K represents the material coefficient.

[0023] Preferably, the minimum section moment of inertia formula is

[0024] I 0 =3W 0 L / K

[0025] Among them, W 0 Indicates the minimum section modulus.

[0026] Preferably, the material coefficient is determined according to the material and yield limit of the barge in combination with design specifications.

[0027] The technical solution of the present invention proposes a method for determining the type depth of a barge based on structural weight control, which solves the problems of the existing barge structure being too heavy, consuming a lot of steel, reducing the loading when the displacement is constant, occupying a lot of ship resources, and being uneconomical, and realizes the selection of the type depth value of the barge that makes the structural weight the lightest. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the relationship between the mold depth and the structure weight in the prior art;

[0029] Figure 2 A schematic diagram of the cross-sectional structural arrangement of a barge provided in an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of a curve showing a change in structural weight with mold depth provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0032] The embodiment of the present invention provides a method for determining the depth of a barge based on structural weight control, comprising the following steps:

[0033] Step 1: Preliminarily determine the main dimensions of the barge (including molded depth) based on the overall performance requirements.

[0034] According to the overall performance requirements, the main dimensions of the barge are initially determined according to the design specifications or the parameters of the parent ship, including the length, width, depth, square coefficient, etc. The depth is recorded as D 1 .

[0035] Taking an actual barge as an example, according to the overall performance requirements, the main dimensions of the barge are preliminarily determined according to the design specifications or the parameters of the parent ship, including the length, width, depth, square coefficient, etc. The depth is recorded as D 1 . As shown in Table 1.

[0036] Table 1 Main dimension parameters of a barge

[0037] parameter Captain L Width B <![CDATA[Mold depth D 1 > <![CDATA[Coefficient of fineness C b > Material coefficient K Numeric 85.7m 15m 5.1m 0.701 0.72

[0038] *Note: This ship adopts CCSDH36 high-strength steel with a yield strength of 355MPa and a material coefficient of 0.72 according to CCS specifications.

[0039] Step 2: Determine the cross-sectional structural layout of the barge.

[0040] Based on the general arrangement drawing, determine the layout of the barge's mid-section structure, including the positions of the main deck, bottom plate, side outer plate, platform deck, longitudinal bulkhead and other main components; determine the form of the barge's mid-section structural skeleton, generally using the longitudinal skeleton; determine the frame spacing s of each plate in the barge's mid-section, usually the frame spacing is between 200mm and 700mm. Since too small a frame spacing is not conducive to construction and the welding residual deformation is too large, and too large a frame spacing will increase the plate thickness and frame size, which is not conducive to weight, s = 400mm is selected here. The structural layout is as follows Figure 2 As shown, the cross-sectional structural layout and structural dimensions of a barge (right half section only, symmetrical on the port side).

[0041] Step 3: Determine the cross-sectional structural dimensions of the barge.

[0042] Based on the structural arrangement in step 2, the thickness of each plate, the size of the longitudinal frame, the size of the longitudinal girders and the size of the strong transverse beam are preliminarily set. The preliminarily set plate thickness and frame size should not be less than the minimum value of the plate thickness and frame modulus calculated for barges in the China Classification Society (CCS) "Rules for Classification of Sea-going Steel Ships". The total longitudinal strength is checked according to the CCS "Rules for Classification of Sea-going Steel Ships", including the minimum section modulus W of the midship transverse section. 0 and minimum section moment of inertia I 0 , see formula (1) and formula (2), C represents the coefficient, and the calculation is performed according to the coefficient determination formula.

[0043] W 0 =CL 2 B(C b +0.7)Kcm 3(1)

[0044] I 0 =3W 0 L / Kcm 4 (2)

[0045] The coefficient C is determined by the following formula:

[0046] When L<90m, C=0.0412L+4; when 90≤L≤300m, When 300<L<350m, C=10.75; when 350≤L≤500m,

[0047] Then, adjust the plate thickness, longitudinal bone size and longitudinal girder size, calculate the midship section modulus W and section moment of inertia I, so that it meets the minimum section modulus W 0 and minimum section moment of inertia I 0 The requirements are met without leaving too much margin. The calculation results are shown in Table 2.

[0048] Table 2 Modulus and moment of inertia of midship cross section at a molded depth of 5.1m

[0049] parameter Midship cross section modulus Moment of inertia of midship cross section The minimum value required by the specification 0.856m3 3.066m4 Calculated value of actual structure 1.146cm3 3.111m4

[0050] Step 4: Calculate the depth D 1 Structural weight W 1。

[0051] According to the structural dimensions and general arrangement drawings determined in step 3, calculate the weight of the hull structure, that is, the molded depth D 1 The structural weight W 1 Here, when the molded depth is 5.1m, the calculated weight of the hull structure is 793.6t.

[0052] Step 5: Determine the optimum depth D for the lightest structure OPT .

[0053] Change the draft depth D to 4.5m, 5.6m, 6.2m, and 7.0m respectively, and repeat steps 3 and 4 to obtain the structural weight at different draft depths, as shown in Table 3.

[0054] Table 3 Structural weight at different depths

[0055] Depth D / m 4.5 5.1 5.6 6.2 7.0 Structural weight W / t 863.4 793.6 748.7 777.3 811.1

[0056] The fitting curve is taken with the mold depth D as the horizontal coordinate and the structure weight W as the vertical coordinate, as shown in Figure 3 As shown in the figure, by using quadratic and cubic polynomial fitting respectively, the depth D that minimizes the structural weight can be found. OPT =5.717m. This type of depth D OPT(5.717m) is the depth of the longitudinal frame structure that meets the requirements of the specification and has the lightest structure weight given the frame spacing s=400mm.

[0057] The technical key points and protection points of the embodiment of the present invention are the method for determining the draft of a barge based on structural weight control, that is, taking into account that the mid-ship cross-section modulus and section moment of inertia are sensitive to changes in draft, the draft is adjusted to perform structural design, check the total longitudinal strength, and calculate the structural weight, so as to obtain the optimal draft that meets the regulatory requirements and has the lightest structural weight.

[0058] The beneficial effects of the barge depth determination method are as follows:

[0059] (1) The embodiment of the present invention proposes a new angle to determine the barge mould depth, that is, the optimal mould depth when the structure weight is the lightest, connects the overall performance with the structural design, and reversely infers the overall main dimension parameters from the structural design, which can provide new ideas for the design of other types of ships;

[0060] (2) The method of determining the depth by the lightest structural weight proposed in the embodiment of the present invention can reduce the structural weight and steel consumption compared with the same type of barge;

[0061] (3) The method of determining the draft by minimizing the weight of the structure proposed in the embodiment of the present invention can reduce the proportion of ship resources occupied by the structure, increase the cargo capacity, and increase the economic benefits compared with the same type of barges.

Claims

1. A method for determining barge depth based on structural weight control, characterized in that: The following steps are involved: Step 1: According to the design specifications or the parameters of the parent ship combined with the overall performance requirements, the main dimensions of the barge are preliminarily determined. The main dimensions of the barge include the length, width, depth, square coefficient and material coefficient; Step 2: Based on the general arrangement drawing, determine the barge mid-section structure layout, the barge mid-section structure skeleton form, and the frame spacing of each plate in the barge mid-section to obtain the initial structure layout drawing; Step 3: According to the initial structural layout, the initial plate thickness and longitudinal bone size are selected in combination with the preset minimum plate thickness and frame modulus. The minimum section modulus and the minimum section moment of inertia are obtained according to the total longitudinal strength verification formula combined with the main dimensions of the barge. The total longitudinal strength verification of the initial longitudinal girder size and the strong crossbeam size is carried out according to the minimum section modulus and the minimum section moment of inertia to adjust the plate thickness, longitudinal bone size and longitudinal girder size; Step 4: Calculate the weight of the hull structure corresponding to the depth according to the adjusted plate thickness, longitudinal bone size, longitudinal girder size and general arrangement drawing; Step 5: Repeat steps 3 and 4 to change the draft depth to obtain different draft depths and the corresponding hull structure weights. Use different draft depths as the horizontal coordinates and the corresponding hull structure weights as the vertical coordinates. Use quadratic and cubic polynomials to fit respectively to obtain the draft depth with the minimum structure weight.

2. A method for determining barge depth based on structural weight control as claimed in claim 1, characterized in that: The cross-sectional structural arrangement of the barge includes the positions of the main deck, the bottom plate, the side outer plate, the platform deck and the longitudinal bulkhead.

3. A method for determining barge depth based on structural weight control as claimed in claim 1, characterized in that: The cross-sectional structural frame form of the barge includes a longitudinal frame type.

4. A method for determining barge depth based on structural weight control as claimed in claim 1, characterized in that: The spacing between the frame members of each plate in the cross section of the barge ranges from 200 mm to 700 mm.

5. A method for determining barge depth based on structural weight control as claimed in claim 4, characterized in that: The spacing between aggregates is determined based on construction convenience, welding residual deformation, plate thickness and aggregate size, combined with the aggregate spacing range.

6. A method for determining barge depth based on structural weight control as claimed in claim 5, characterized in that: The spacing between the aggregates is selected to be 400 mm.

7. A method for determining barge depth based on structural weight control as claimed in claim 1, characterized in that: The total longitudinal strength verification formula includes a minimum section modulus formula and a minimum section moment of inertia formula.

8. A method for determining barge depth based on structural weight control as claimed in claim 6, characterized in that: The minimum section modulus formula is: W0=CL 2 B(C b +0.7)K Among them, C represents the coefficient, L represents the length of the ship, B represents the width of the ship, and C b represents the square coefficient, and K represents the material coefficient.

9. A method for determining barge depth based on structural weight control as claimed in claim 6, characterized in that: The minimum section moment of inertia formula I0=3W0L / K Where W0 represents the minimum section modulus.

10. A method for determining barge depth based on structural weight control as claimed in claim 1, characterized in that: The material coefficient is determined according to the material and yield limit of the barge in combination with the design specifications.

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